Cause–Effect Pairing:\nI) State X imposes a higher sales tax on petroleum products than neighboring states.\nII) All petrol pumps in the state observe a “bandh” in protest.

Introduction / Context:
The stems describe a policy action (tax increase) and an organized protest (bandh). We must identify the direction of causality.

Given Data / Assumptions:

• I) Higher sales tax on petroleum products in State X vs. neighbors.
• II) Statewide petrol pump bandh in protest.

Concept / Approach:
Industry protests commonly follow price/tax hikes that reduce margins or demand. The bandh is a direct response to I.

Step-by-Step Solution:
1) The policy shock (I) provides immediate grievance.2) Collective action (II) is a plausible effect.3) Reverse causality (II → I) lacks logic: protests do not precede a change they are protesting.

Verification / Alternative check:
Temporal sequence and motive alignment favor I → II.

Why Other Options Are Wrong:
(b) reverses order; (c) and (d) deny linkage despite obvious protest-cause structure.

Common Pitfalls:
Overcomplicating straightforward policy–protest relationships.

Final Answer:
I is the cause; II is its effect.