Final answer:
The subject of this question is English. It involves understanding the sequence and timing of events in a story or narrative.
Step-by-step explanation:
The subject of this question is English. It involves understanding the sequence and timing of events in a story or narrative.
In this scenario, John sends a letter rejecting Arlene's offer on Tuesday morning. However, later in the same day, he changes his mind and sends a letter of acceptance. For the letter of acceptance to be effective, it needs to be received by Arlene before she receives the rejection.
This question involves analyzing the events and timeline in a story, which falls under the subject of English.