OFFICIAL EXPLANATION
The amount of personal vehicles being used not only causes pollution but also affects the economy.A. amount of personal vehicles being used not only causes pollution but also affects the economy
Incorrect.
This answer choice is grammatically incorrect. The article the amount of can describe non-count nouns only whereas the noun vehicles is a count noun.
What helps you identify this mistake is the following Stop Sign:
much, (a) little, less, the amount of
B. number of personal vehicles being used causes not only pollution but also affects the economy
Incorrect.
Although this answer choice corrects the original Parts of Speech error by replacing amount with number to match the plural count noun vehicles, it is grammatically incorrect. The same part of speech that follows not only should follow but also. In this answer choice a noun (pollution) follows not only, while a verb (affects) follows but also.
What helps you identify this question as a Parallelism question as well as identify the mistake is the following Stop Sign:
C. number of personal vehicles being used not only causes pollution but also affects the economy
This answer choice corrects the original Parts of Speech error by replacing amount with number to match a plural count noun (personal vehicles). It also maintains Parallelism while using the structure not only X but also Y.D. number of personal vehicles being used not only causes pollution but also an economic effect
Incorrect.
Although this answer choice corrects the original Parts of Speech error by replacing amount with number to match the plural count noun personal vehicles, it is grammatically incorrect. The same part of speech that follows not only should follow but also. In this answer choice a verb (causes) follows not only, while a noun (economic effect) follows but also. E. number of personal vehicles being used not only causes pollution but affects the economy
Not quite.
Although this answer choice corrects the original Parts of Speech error by replacing amount with number to match the plural count noun personal vehicles, it is grammatically incorrect. Not only cannot be followed by and also.