Exam question bothering me [closed]
Solution 1:
Option B is correct. "Last summer" is entirely in the past, so you also refer to actions that took place then in the past tense.
Option A uses present perfect tense, which indicates an action that is ongoing or has continued until the present. You would use that tense if you were referring to a time period that includes right now (e.g. "this week" or "since last summer").