AbhishekDhanraJ72 wrote:
I thought increase is used for comparing same product and more is used for comparing different products. I have read from some some expert's explanation. Please someone clears my doubt.
While there is some truth to what you're saying, to answer Sentence Correction questions correctly, we have to carefully analyze each sentence version rather than simply base our selection on a pattern that may not apply in a particular context. So, let's analyze the correct version in this question.
The correct version is the following:
The number of undergraduate degrees in engineering awarded by colleges and universities in the United States more than doubled from 1978 to 1985.Notice that, in this context, "doubled" is synonymous with "increased." "Doubled" means "increased to become double in size." So, we can see that this sentence actually does follow your rule of "increased" being used for discussing what happened to the same thing.
So, then "more" is used to qualify the increase. "More than doubled" means "increased to become more than double in size."
Since it makes sense that the number of degrees increased to become more than double in size, the correct version effectively conveys a meaning that makes sense.