In the following question, the sentence given with blank to be filled in with an appropriate word. Select the correct alternative out of the four and indicate it by selecting the appropriate option.
If I ________ you, I would buy this mobile phone.

The correct option is C.
This sentence represents a second conditional clause, which deals with an unreal or imaginary present/future situation. In such subjunctive clauses, the past subjunctive form "were" is used for all persons (including "I", "he", "she", "it"), regardless of whether the subject is singular or plural.