a. suggest that at least a portion of the area was remaining
--- wrong verb number
b. suggest at least a portion of the area remaining
----- wrong verb numberc. suggests that at least a portion of the area remained
---- CORRECTd. suggests at least a portion of the area that had remained
----- Wrong meaning. "a portion" cannot be suggested, an action can be suggested. Therefore, we need "suggests THAT subject + verb. e. suggests at least a portion of the area to have remained
--- Wrong meaning. "a portion" cannot be suggested, an action can be suggested. Therefore, we need "suggests THAT subject + verb. _________________
GMAT Elimination System: "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."
GMAT Motivation: "The GMAT never sleeps. She waits in bed for you, one eye open. And if you are not careful, one day you wake up and she's gone."