The Damodar Tribeni canal in eastern India, which serves as both an irrigation and navigation canal, has a total length of approximately how many kilometres?

Introduction / Context:
Canals that serve both irrigation and navigation functions have played a significant role in the economic development of river valleys in India. The Damodar Tribeni canal in eastern India is one such system associated with the Damodar River region. This question tests factual knowledge of its approximate total length in kilometres.

Given Data / Assumptions:
• The canal mentioned is the Damodar Tribeni canal. • It provides both irrigation water and navigation facilities. • The question seeks its approximate total length in kilometres. • Options range from 137 km to 177 km in steps of 10 km.

Concept / Approach:
This is a direct recall question where the value must be known from reading or memorisation. Standard Indian geography objective question banks give the length of the Damodar Tribeni canal as about 137 km. Therefore the approach is to match this remembered figure with the closest option.

Step-by-Step Solution:
Step 1: Recall the canal system in the Damodar valley, including the Damodar Tribeni canal. Step 2: From general knowledge sources, remember that its length is stated to be about 137 km. Step 3: Compare this value with the answer choices provided in the question. Step 4: Option A gives 137 km, while other options provide larger values of 147, 157, 167 and 177 km. Step 5: Since 137 km matches the widely cited figure, select 137 km as the correct answer.

Verification / Alternative check:
Multiple competitive exam guides that cover Indian rivers and canals list the Damodar Tribeni canal length specifically as around 137 km. In tables summarising major canals, this figure is repeatedly used for this canal. Cross checking with such tables adds confidence that 137 km is the expected exam answer.

Why Other Options Are Wrong:
147 km: This slightly higher figure is a distractor and is not the standard value used in exam references. 157 km: Another plausible looking number, but it does not match the usual 137 km figure. 167 km: Too high compared with the commonly cited length of the Damodar Tribeni canal. 177 km: Also higher than typical textbook and question bank values, included mainly to test exact recall.

Common Pitfalls:
Learners often confuse similar looking numbers when several options are separated by only 10 km differences. Another pitfall is to estimate length based on intuition rather than memorising the exact value from reliable sources. Taking brief notes of important canal statistics such as length, command area and function can help during revision.

Final Answer:
The Damodar Tribeni canal has an approximate total length of 137 km.