(A) low and advertising expenses are high as retailersprepare
Correct
(B) low and their advertising expenses are high as they prepare
their doesn't have a logical referent, only plural referents are "revenues" and "spring months", both of which can't logically have a revenue
(C) low with higher advertising expenses in preparation
"higher" indicates a comparison, but we don't have a comparison, so we are left to ask higher than what? Also usage of "with"
...
Correct
(B) low and their advertising expenses are high as they prepare
their doesn't have a logical referent, only plural referents are "revenues" and "spring months", both of which can't logically have a revenue
(C) low with higher advertising expenses in preparation
"higher" indicates a comparison, but we don't have a comparison, so we are left to ask higher than what? Also usage of "with"
...









