The correct option is C If I were the prime minister of the country, I would
‘Was is associated with the past tense. The usage of ‘was’ in the given sentence is incorrect.
In discussing hypothetical situations, the subjunctive mood is used.
The correct usage is ‘If I were…I would….’
Also note that ‘would’ is used instead of ‘will’: In general, would is used in situations which are hypothetical, or contingent on some unfulfilled condition; will is used in situations that are more certain.