a. Gill felt justified in his suspicion of Randy Brill.
Explanation:
Option A is the correct answer.
From the excerpt, we discover that Gill has taken time to learn about Randy Brill's sinister reputation even though it was once they met. One can deduce that this makes Gill feel justified to be suspicious of Randy Brill.
Also, the detective is one who actually has an innate suspicion for politicians. As a private detective, he tends to learn about politicians and to know the dark side of humans.
