In the history of medieval India, which ruler is widely credited with building and improving the Grand Trunk Road, the long highway connecting various parts of northern India?

Introduction / Context:
This question concerns medieval Indian infrastructure and administration. The Grand Trunk Road is one of the oldest and longest highways in the Indian subcontinent, connecting regions from Bengal to the northwestern frontier. While various rulers contributed to its maintenance, one medieval ruler is especially remembered for constructing and improving this road on a large scale. Exams often test this association as a key fact of medieval Indian history.

Given Data / Assumptions:
- The question asks which ruler is credited with building and improving the Grand Trunk Road.
- The options list Krishnadeva Raya, Babur, Sher Shah Suri, Jahangir and Akbar.
- We assume the question refers to the major reconstruction and extension of the road during the mid sixteenth century.

Concept / Approach:
Sher Shah Suri, founder of the Sur Empire, is widely credited with constructing and significantly improving the road which later came to be known as the Grand Trunk Road. He connected Sonargaon in Bengal to the Indus region and introduced rest houses, milestones and planted trees along the route. Although later Mughal rulers, including Akbar, maintained and used the road, Sher Shah Suri is the central figure in its development. The approach is to recall which ruler is most strongly associated with this highway in standard history books.

Step-by-Step Solution:
Step 1: Identify that the question is about a major road project covering long distances across northern India. Step 2: Recall that Sher Shah Suri undertook extensive road building as part of his administrative reforms. Step 3: Remember that he constructed a road from Bengal to the northwestern frontier, adding sarais, trees and milestones. Step 4: Note that Babur was mainly a conqueror who founded the Mughal Empire but did not focus on such an extensive road project. Step 5: Recognise that Krishnadeva Raya ruled the Vijayanagara Empire in the south and is not associated with the Grand Trunk Road, and that Akbar and Jahangir came later and mainly used and maintained the road built by Sher Shah.

Verification / Alternative check:
Verification can be done by recalling that many textbooks describe Sher Shah as a great administrator who standardised currency, improved revenue administration and built roads and sarais. The Grand Trunk Road is frequently mentioned in that context. While later Mughal emperors maintained this route, the name of Sher Shah Suri is always linked with its major construction and improvement. This repeated association in educational material confirms that Sher Shah Suri is the answer.

Why Other Options Are Wrong:
Krishnadeva Raya: A powerful ruler of the Vijayanagara Empire in south India, not associated with the Grand Trunk Road of northern India.
Babur: Founder of the Mughal Empire, but his short reign did not focus on long distance road building of this scale.
Jahangir: Known for his interest in justice and travel, but not credited with building the Grand Trunk Road.
Akbar: A major Mughal emperor who used and possibly improved existing routes, but it is Sher Shah Suri who is singled out for constructing the Grand Trunk Road in standard histories.

Common Pitfalls:
Students sometimes mistakenly choose Akbar because he is a well known Mughal emperor associated with many reforms. Another mistake is to underestimate Sher Shah Suri due to his relatively short reign. Remembering Sher Shahs contributions, including standard coinage, revenue reforms and road building, helps fix his name to the Grand Trunk Road. Also, noting that Krishnadeva Raya belongs to southern India prevents mixing regional histories.

Final Answer:
The ruler credited with building and improving the Grand Trunk Road is Sher Shah Suri.