so far below

[keannu]

Can't c(much) be an answer? It sounds quite natural, but I don't know why...

A: Did you read Todd Farmer's new mystery novel?
B:Yes, but if fell so __b___ below my expectations.
a)right b)far c)much d)very

[Raymott]

Can't c(much) be an answer? It sounds quite natural, but I don't know why...

A: Did you read Todd Farmer's new mystery novel?
B:Yes, but if fell so __b___ below my expectations.
a)right b)far c)much d)very

Either way, the sentence seems incomplete. "So", here, seems to need a resolution.
"Yes, but if fell so far below my expectations that I'm sorry I read it."
In contemporary uses of "so", an extra word is not needed there. "It fell so below my expectations" (I don't endorse this usage).