Correct
BunuelWannabe.
Grammatically, the difference is:
(i)
Rising cost:
Rising is used as an
adjective (participle), modifying
cost. So,
cost is the subject
(ii)
The rising of costs:
Rising is used as a
noun (gerund, as you mentioned in your earlier post). So,
rising is the subject
As mentioned in my earlier post, if the intent is to depict
rising as a
noun, I would have preferred a pure-play noun
rise.
Meaning-wise, the difference is:
(i)
Rising cost: Costs that are
in the process of rising (as Ajitesh mentioned)
(ii)
The rising of costs: Does
not explicitly suggest that the process of rising is
still underway. In fact, it suggests that the
rise itself (and not the
process of rising) is being discussed.
For this question, a case can be made for either (i) or (ii); however, also notice that (A) and (C) also differ in
costs vs
cost. Since we have
cost in the non-underlined portion (
lower cost), it would be preferable to go with
cost in the underlined portion as well.