At the most the answer for the second blank is D. The composer tried to drive out what was inside his own soul

The first blank describes the concerti (and the composer) as having "fits of passion" that "give way to sudden idylls" - meaning quick, unpredictable changes in mood or style.
- Mercurial means "subject to sudden or unpredictable changes of mood" - that fits perfectly.
- Rambling (unfocused, long-winded) doesn't match the sudden shifts between passion and idyll.
- Torrid (full of strong emotions, usually passion) doesn't capture the changeability.

So (A) mercurial is correct for the first blank.

The second part says: the composer's music had these shifts "as though" he was trying to $\_\_\_\_$ the conflicts within himself.

If the music moves from passion to calm suddenly, it's as if he's trying to expel or resolve his inner conflicts through the music.
- Exorcise means to drive out or purge - fits the idea of getting inner conflicts out through the music.
- Mirror would mean just reflect, not resolve.
- Foreshadow doesn't fit the context of internal conflict.

So (D) exorcise is correct for the second blank.

Final answer:
(A) mercurial
(D) exorcise