Kazan was quickly (i)__criticize__ by many of his contemporaries for his transgression, who saw his testimony as treachery, an act of (ii)___treachery__ which stained how they viewed him both as an artist and as a man. It was only by continually making films that he was able to (iii)_make amends__ his perceived sins and achieve some measure of atonement.
if we see the guess answers and see the world given below, we can find B and C doesn't meant criticize but rebuked mean criticize and perfidy means treachery and by make amends is synonymous of expiate. so A,D, and I is answer.

[quote="Carcass"]

Kazan was quickly (i)____________ by many of his contemporaries for his transgression, who saw his testimony as treachery, an act of (ii)____________ which stained how they viewed him both as an artist and as a man. It was only by continually making films that he was able to (iii)____________ his perceived sins and achieve some measure of atonement.

Blank (i)	Blank (ii)	Blank (iii)
(A) rebuked	(D) perfidy	(G)exacerbate
(B) lauded	(E) sophistry	(H) deviate
(C) mitigated	(F) redemption	(I) expiate

We know that Kazan made a transgression, and his contemporaries were displeased with it (..saw his testimony as treachery).Therefore, we need a strong word of condemnation for the first blank. Only rebuked fits the bill.

His contemporaries saw his testimony as treachery, hence the next phrase which continues describing his actions (an act of ____) should also convey a similar idea. The only word that fits the bill is perfidy, which describes a state of being untrustworthy and deceitful, and is closely related to treachery. Since he works to atone for his sins, sophistry cannot be the choice for the second blank. It is not strong enough word. Also it is not very closely related to treachery as perfidy is.

And since he achieved some measure of atonement, by continually making films, expatiate is the word for the third blank.

Why is sophistry wrong? Sophistry means the use of deceptive reasoning or argumentation to cheat. And the blank directly related to his testimony. Perfidy seems more general here, as opposed to sophistry.

Let's go step-by-step.

First blank
"Kazan was quickly \($\_\_\_\_$\) by many of his contemporaries for his transgression, who saw his testimony as treachery..."
- Transgression $\(\rightarrow\)$ something bad he did.
- They saw it as treachery $\(\rightarrow\)$ so they condemned/criticized him.
- rebuked $=$ criticized or reprimanded $\(\rightarrow\)$ fits.
- lauded $=$ praised $\(\rightarrow\)$ opposite meaning, doesn't fit.
- mitigated = made less severe $\rightarrow$ doesn't fit for what his contemporaries did to him (mitigate is something you do to a problem, not to a person for a transgression).
So Blank (i) = A. rebuked.

Second blank
"...his testimony as treachery, an act of _______ which stained how they viewed him..."
- "Treachery" means betrayal.
- perfidy $=$ treachery, betrayal of trust $\rightarrow$ perfect match.
- sophistry = clever but false reasoning $\rightarrow$ not the same as betrayal.
- redemption $=$ saving from $\sin \rightarrow$ opposite idea.

So Blank (ii) = D. perfidy.

Third blank
"It was only by continually making films that he was able to _______ his perceived sins and achieve some measure of atonement."
- "Atonement" means making amends for sin.
- expiate $=$ atone for, make amends for $\(\rightarrow\)$ fits exactly.
- exacerbate $=$ make worse $\rightarrow$ opposite.
- deviate = depart from $\(\rightarrow\)$ doesn't fit.

So Blank (iii) = I. expiate.

Final answer:
A, D, I