Analogy: Letter is to Telegram as Train is to ____. Identify the faster, more rapid alternative within the same broad domain (communication ↔ transport).

Introduction / Context:
Analogies often compare a slower method with a faster, technologically advanced alternative in the same domain. Telegrams historically delivered messages faster than letters. We must find the transport counterpart to “train.”

Given Data / Assumptions:

• Letters vs telegrams: both communication modes; telegram is faster.
• Trains vs other transport: seek a faster alternative analogous to “telegram.”
• Options mix communication and transport terms; domain must match the second pair.

Concept / Approach:
The underlying relation is “slower method : faster method within same domain.” Letter→telegram (communication). Train→aeroplane (transport). Telephone is communication (wrong domain for the second term); horse is older/slower; messenger is a person, not a transport mode.

Step-by-Step Solution:
Identify domain parity: communication ↔ transport.Map speed hierarchy: train (slower) vs aeroplane (faster).Eliminate cross-domain or non-mode distractors.

Verification / Alternative check:
Substitution test: “As a telegram is a faster way to send a message than a letter, an aeroplane is a faster way to travel than a train.”

Why Other Options Are Wrong:
Telephone: communication domain, mismatched. Horse: typically slower than a train. Messenger: person, not a transport mode.

Common Pitfalls:
Picking “telephone” by echoing the first domain; the second pair must remain within transport modes.

Final Answer:
Aeroplane.