Final answer:
The correct answer is a. she'll have finished, which uses the future perfect tense to indicate that the action of finishing her autobiography will be completed by the end of the year.
Step-by-step explanation:
The correct answer to the question is: a. she'll have finished her first autobiography by the end of the year. This sentence requires the use of the future perfect tense, which is used to describe an action that will be completed before a specific time in the future. The structure consists of will have + past participle. In this case, 'finished' is the past participle of the verb 'finish'.
Option b, she'll be finished, is grammatically incorrect in this context. Option c, she has finished, is in the present perfect tense and does not convey future completion. Option d, she's going to have finished, could technically be used but is less common in this context and sounds more informal and less definitive than the future perfect tense.
The use of the future perfect tense emphasizes the completion of the action (writing her autobiography) by a certain future time (the end of the year). This tense helps to create a clear timeline about future events or actions that are expected to be completed before another point in time.