Statement:\n“India will not withdraw its troops from the border until it is satisfied that cross-border infiltration has ended.” — US Defence Secretary (reporting India’s stance)\nConclusions:\nI. India has an optimum number of troops to sustain internal peace.\nII. Infiltration is a serious problem.

Introduction / Context:
The statement ties troop withdrawal to cessation of infiltration. We must identify what necessarily follows.

Given Data / Assumptions:

• Troops are at the border; withdrawal is conditional on ending infiltration.
• No claim is made about internal peace levels or “optimum” troop numbers.

Concept / Approach:
Linking withdrawal to infiltration’s end indicates the latter is a significant concern (serious enough to dictate posture). It says nothing about overall troop sufficiency for internal peace, which is a different question.

Step-by-Step Solution:
1) I introduces “optimum” and “internal peace” — neither term appears or is implied → I does not follow.2) II: The insistence on holding positions until infiltration ceases reflects seriousness → II follows.

Verification / Alternative check:
If the statement had assessed internal troop adequacy, I could follow; it does not.

Why Other Options Are Wrong:
Only I / Either / Neither: each ignores the explicit conditional linkage indicating seriousness of infiltration.

Common Pitfalls:
Reading internal-security judgments into a border-posture statement.

Final Answer:
if only conclusion II follows