Which transition phrase introduces a comparison?
at this time
in brief
in addition
on the other hand

The transition phrase that introduces a comparison is option D. On the other hand.

On the other hand is a phrase employed in texts in order to create a contrast and to show the difference between the statement that this phrase introduces and a notion mentioned before. The complete idiom is "on the one hand, on the other hand," and it is a resource usually used in essays focused on the comparison and constrast of two different aspects, characteristics or issues regarding to a topic.

d

explanation:

the answer would be c