In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No Error'.
A unique feature of a mobile phone (A)/ is that it enables seamless telephone calls even (B)/ when the user are moving around wide areas. (C)/ No error (D)

Answer

3

Explanation

Here, when the user is moving around wide areas is the right usage.