Final answer:
Sentence 27 should be rewritten as, 'There in my guitar case were the keys,' to ensure correct subject-verb agreement.
The correct Option is 27 is d.
Step-by-step explanation:
The correct way to rewrite sentence 27 is d. There in my guitar case were the keys. The sentence requires the plural form of the verb 'to be' (were) to agree with the plural noun 'keys'. Previous grammatical constructs in the passage such as 'the keys aren’t here' and 'our guitar cases sure do' also indicate that the correct verb form should be 'were', and not 'was'.
The correct way to rewrite sentence 27 is:
There in my guitar case were the keys.