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'.
He was not (1)/ grateful for (2)/ Rahul for helping his cause. (3)/ No error (4)
Identify the most appropriate option to substitute the underlined segment. If no substitution is required, select No substitution. The shoebill stork can be recognise from its long legs and broad wings.