Assertion–Reason (Holiday rail demand)\nAssertion (A): The Indian Railways will run many special trains during the holiday season.\nReason (R1): There is a lot of movement of people during the holiday season across the world (and in India).\nReason (R2): Trains become overcrowded during the holiday season.\nSelect which reason(s) truly explain A.

Introduction / Context:
Transport systems add capacity when demand spikes. The question is whether general surge in holiday travel (R1) and observed overcrowding (R2) both justify running special trains (A).

Given Data / Assumptions:

• A: Railways will run multiple specials in holiday periods.
• R1: Holiday seasons involve large population movements.
• R2: Trains become overcrowded during these times.
• Railways can deploy temporary capacity to manage demand and alleviate crowding.

Concept / Approach:
Supply–demand logic: heightened demand (R1) is a direct cause for adding capacity; overcrowding (R2) is a symptomatic indicator of insufficient capacity and hence a practical reason to add trains.

Step-by-Step Solution:

Verification / Alternative check:
Historically, rail and bus systems issue extra services on festivals, summer vacations, and long weekends precisely due to R1 and R2.

Why Other Options Are Wrong:
A or B alone understate the planning plus mitigation rationale; D denies clear operational reasons.

Common Pitfalls:
Treating R2 as only an effect; in planning terms, overcrowding is also a prompt to add services.

Final Answer:
If both (R1) and (R2) are reasons for the assertion (A).