In the river and city analogy "Agra : Yamuna :: Varanasi : ____", which river correctly completes the pair?

Introduction / Context:
This question tests your knowledge of important Indian cities and the rivers that flow through them. The analogy "Agra : Yamuna" shows a relationship between a city and the major river on whose banks it lies. You need to continue the same relationship for the holy city of Varanasi. Such questions are very common in general knowledge and competitive exams.

Given Data / Assumptions:

• The first pair is "Agra : Yamuna".
• The second pair is "Varanasi : ____".
• Options include several Indian rivers: Damodar, Betwa, Ganga, Son, Narmada.
• We assume standard geographical facts taught in school level textbooks.

Concept / Approach:
Agra is a famous city in Uttar Pradesh, and the river flowing by it is the Yamuna. This tells us the pattern is "city : river". Varanasi, also known as Kashi or Banaras, is one of the oldest and most sacred cities of India. It is famously situated on the banks of the river Ganga. Therefore, we must pair Varanasi with Ganga to maintain the same type of relationship that exists in the first pair.

Step-by-Step Solution:

Step 1: Recognise that Agra is located on the banks of the Yamuna, giving the pattern "city : its main river". Step 2: Identify Varanasi as a major religious city in Uttar Pradesh. Step 3: Recall that Varanasi is situated on the banks of the river Ganga. Step 4: Check each option to see which river flows by Varanasi. Step 5: Confirm that Ganga is the correct river associated with Varanasi.

Verification / Alternative check:
Damodar flows mainly through Jharkhand and West Bengal. Betwa flows through Madhya Pradesh and Uttar Pradesh but is not primarily associated with Varanasi. The river Son is also not the main river of Varanasi. Narmada flows through central India but is associated with cities like Jabalpur. Only the Ganga is directly connected in textbooks and general knowledge with the ghats of Varanasi where pilgrims bathe and perform rituals.

Why Other Options Are Wrong:
Damodar, Betwa, Son and Narmada all flow in different regions and are associated with other towns and cities. They do not form the classic and well known pair with Varanasi that Ganga does. Selecting any of them would break the consistent "city : correct river" pattern that is established by the first pair.

Common Pitfalls:
Some aspirants may confuse rivers in Uttar Pradesh or pick Betwa or Son because they also lie in North India. Others might not clearly remember the precise river for each city. Regular revision of important river city pairs is essential, as they form a common part of general awareness sections in many exams.

Final Answer:
The correct completion of the analogy is "Agra : Yamuna :: Varanasi : Ganga".