Statement: Ramesh decided to obtain railway reservation in February for a journey he plans to make in May to Chennai. Assumptions: I. Railways issue reservations three months in advance. II. There is more than one train to Chennai. III. Seats/berths will be available in the desired class when he books.

Introduction / Context:
The action (booking in February for a May trip) presupposes certain facts about reservation windows and expected availability. We evaluate which assumptions are necessary.

Given Data / Assumptions:

• Target month of travel: May.
• Booking attempt in: February.
• Destination: Chennai.

Concept / Approach:
For an action to be rational, the actor must presume it is possible (window open) and worthwhile (tickets likely available).

Step-by-Step Solution:
I: If reservations are not released three months ahead, booking in February would be impossible. Thus I is implicit.II: The number of trains is irrelevant; even a single train suffices. Not implicit.III: He must expect availability in his class; otherwise the early booking decision would not serve its purpose. Implicit.

Verification / Alternative check:
Even if multiple trains exist, the decision does not rely on that fact; it relies on window timing and availability expectations.

Why Other Options Are Wrong:

• II and III / All: include unnecessary II.
• Only I / Only III: each omits the other necessary assumption.

Common Pitfalls:
Do not add irrelevant facts (number of trains) as assumptions.

Final Answer:
I and III are implicit.