Statement:\nPrabodh wrote a second letter to his mother after a month because he did not receive any reply to the first letter.\n\nAssumptions:\nI. Prabodh’s mother did not receive the first letter.\nII. Letters generally reach within a fortnight under normal circumstances.\nIII. His mother usually replies to his letters promptly.\n\nWhich of the above assumptions are implicit?

Introduction / Context:
Sending a follow-up letter after a month suggests expectations about postal timelines and the recipient’s responsiveness. We must identify which beliefs are necessary for Prabodh to consider one month of silence unusual enough to warrant writing again.

Given Data / Assumptions:

• Event: Second letter sent after one month due to no reply to the first.
• Assumption I: Mother did not receive the first letter.
• Assumption II: Postal delivery usually takes much less than a month (e.g., within a fortnight).
• Assumption III: Mother typically replies promptly.

Concept / Approach:
The rational trigger is a deviation from expected turnaround time. That requires beliefs about normal mail duration and the mother’s normal response behavior. Whether the first letter was actually received is uncertain; the act does not require assuming non-receipt—only that a month without reply is atypical.

Step-by-Step Solution:

Verification / Alternative check:
Even if the first letter arrived, delayed or missing replies would still rationalize writing again given the expectations in II and III.

Why Other Options Are Wrong:

Common Pitfalls:
Equating “no reply” with “no receipt.” The action follows from violated expectations, not certainty about delivery failure.

Final Answer:
Assumptions II and III are implicit.