Option A is correct. To service a miss, we'd have to introduce the block in the cache. Smaller the block size, smaller is the service time.
Option B is incorrect. Spatial locality would be the neighbouring pages of a page. The larger the block size, the more neighbours it could take in.
Option C is incorrect. If the block offset field is reduced, Tag field would expand.
Option D is incorrect. The hit time solely depends on the comparators.