Explanation
Correct Answer: (c) will have completed
Detailed Explanation
This question tests your understanding of action timelines, specifically signaled by the time expression "By next year".
Whenever a sentence uses the preposition "By" followed by a specific future time reference (e.g., by tomorrow, by next month, by 2027), it implies that an action will be finished or completed before that specific point in the future arrives. This requires the Future Perfect Tense.
The mathematical grammatical structural formula for the Future Perfect Tense is:
Subject+will have+V3 (Past Participle form of the verb)+Object
Let's break down the sentence components:
Time Marker: "By next year" ⟹ indicates a future deadline.
Subject: "she"
Verb Structure: Following our rule, we apply will have followed by the third form (V3) of complete, which is completed.
Thus, the complete grammatically correct sentence is: "By next year, she will have completed her degree."