Correct the sentence at the underlined point.
Let's go for a walk, shouldn't we?
The correct option is C shall we
Option A is the correct answer. The first part of the sentence being a proposal, the question tag is also a suggestion, and not permission, as indicated by options B and C. Moreover, since the tense in the first part of the sentence is in the present, the question tag should also be in the present tense. Thus, Options B,C and D are all incorrect.