Answer:
The sentence in which the underlined modifier in the comparative degree is:
b. Seaside towns grew more quickly than inland towns.
Step-by-step explanation:
'More quickly' is the comparative degree of the adjective in the sentence. There are three degrees of comparison of adjectives. The first is the positive degree in which no comparison is made. The second is the comparative degree in which a comparison is made between two things or person. The third is the comparison made between two or more things.