suspicious about?

涂于德

Because of long drought，the farmers are ______ about the prospect of a good yield.
A) sure   B) doubtful  C) suspicious  D) doubting

I know the Chinese for this sentence.
由于长期干旱，农民对于良好的收成前景充满了疑虑。
I wonder which to choose, B or C? What’s the biggest difference between the two words?

xiao100

suspicious of
doubtful about

意思一样