The question asks about the longest tributary river in India. Let's examine the options provided and understand what a tributary river is.

Understanding Tributary Rivers in India

A tributary is a stream or river that flows into a larger river or lake. It does not flow directly into a sea or ocean. The main river system is often formed by the joining of several tributaries.

Analyzing the Options

• Beas: The Beas River is a river in North India. It is a tributary of the Indus River. While important, it is not the longest tributary in India.
• Ganges: The Ganges (or Ganga) is a major river in India, considered a holy river. It is not a tributary itself but is the main river into which many tributaries flow, including the Yamuna.
• Ravi: The Ravi River is part of the Indus River system. It flows through India and Pakistan and is a tributary of the Chenab River, which eventually joins the Indus. It is not the longest tributary in India.
• Yamuna: The Yamuna River, also known as Jamuna, is a major river in Northern India. It originates from the Yamunotri Glacier in the Himalayas. It flows through several states before joining the Ganges River at Triveni Sangam, Allahabad (Prayagraj).

The Yamuna River as the Longest Tributary

The Yamuna River is the longest tributary of the Ganges River. Its approximate length is around 1,376 kilometers (855 miles). Many important cities like Delhi, Agra, and Mathura are located along its banks.

Comparing the lengths of the options given as tributaries:

Based on the lengths, the Yamuna River stands out as the longest among the tributaries listed and is widely recognized as the longest tributary river in India.

Conclusion: Longest Tributary in India

Considering the options and general knowledge of Indian rivers, the Yamuna River is indeed the longest tributary river in India.