Statement: Mohan asked his mother to arrange food for about thirty persons because he invited all his friends to celebrate his birthday.\nAssumptions:\nI. Most of Mohan’s friends are likely to come to his house on his birthday.\nII. There will not be more than thirty attendees at the party.

Introduction / Context:
Provisioning for thirty implies an attendance estimate based on invitations. We must identify the necessary presupposition for this request.

Given Data / Assumptions:

• “All friends” invited; headcount requested ≈ 30 portions.
• No exact RSVP list.

Concept / Approach:
Ordering for thirty assumes many invitees will attend (I). It does not require certainty that attendees will not exceed thirty (II); “about thirty” already expresses uncertainty and tolerance around the estimate.

Step-by-Step Solution:
1) If few friends were expected, arranging food for thirty would be wasteful; hence I is necessary.2) II is too strict; Mohan can still order “about thirty” acknowledging possible variance.

Verification / Alternative check:
Event catering commonly works with approximate counts; slight over/under is acceptable.

Why Other Options Are Wrong:
They either overconstrain attendance or deny the evident expectation of turnout.

Final Answer:
Only Assumption I is implicit.