what did who imply? and what are you talking about?
The best answer would be Letter B - to entertain.
The author merely would like to provide amusement to the readers at his expense. It certainly does not persuade, explain, nor inform anything since it states - <span>But why bother with the descriptions; you’ve probably already grasped the idea!</span> - which could be taken as a witticism.
Answer B. (Future perfect tense is used, as the sentence refers to something that will be completed by some point in the future.) is correct.
B is correct because the event which will happen in the future (the baking of the cakes) will also have ended.
I will have baked is a correct form of future perfect, because future perfect is made with the following construction:
Subject + will have + past participle