Its saying "not" just before the blank . Thats why . If you put vulnerable then it become not vulnerable , which is incorrect (actually the report is vulnerable ) . Thats why impregnable is the right fit .

The report, (i) $\(\qquad\)$ from the company's own internal documents, revealed that its network was in fact not (ii) $\(\qquad\)$

Blank (i)	Blank (ii)
A. coerced	D. vulnerable
B. gleaned	E. implacable
C. redacted	F. impregnable

"in fact" is suggestive.

The correct words for the blanks are (i) gleaned and (ii) impregnable.

Breakdown of the Blanks
- Blank (i): B. gleaned

The sentence states that the report came from the company's "own internal documents." Gleaned means to collect information from various sources, which fits the context of compiling a report from internal records.
- Blank (ii): F. impregnable

The word "not" sets up a contrast. The report revealed that the network was not something. Since the report came from internal documents, it likely revealed a problem with the network. Impregnable means unable to be captured or broken into. If the report revealed the network was "not impregnable," it means the network was, in fact, vulnerable. This makes logical sense in the context of the sentence.

The Complete Sentence
"The report, gleaned from the company's own internal documents, revealed that its network was in fact not impregnable."