Which sentence has a gerund functioning as object of a preposition

Ineed . identify the item that shows sharp and vivid details rather than vague and general ones (put a or b for your answer.) a. nearly all people at times suffer from depression, which can be triggered by something as small as a c-minus on a quiz. they may become so depressed that they can’t even answer the phone or get out of bed. b. nearly all people feel sad at times and think things are hopeless. depressed by some event or circumstance, they may be unable to perform even the simplest activities they normally do every day.