OE
The first blank options all involve some sort of unreliability, but the relevant clue is that Garth’s behavior was “improbably” well-received by his boss, who is a hypochondriac. Since stealing (embezzler or pilferer) has nothing to do with health, malingerer (someone who fakes illness) fits best.
The second blank asks for something similar to “hypochondriac.” The boss may be casuistic (practicing clever but unsound reasoning) or imposing (grand and impressive in appearance), but it’s only his trepidatious (in a state of fear that something may happen) character that ties well with hypochondria. The last blank is a word similar to “foresight”; only sagacity fits. Insipidity (boringness, dullness) and temerity (excessive confidence, audacity) don’t agree with “foresight.”
Answer: B,F,H