Case-1: Let the person be type 1. Type 1 always tells truth.
So the statement "toss is head if and only if I am telling the truth" is true .
So toss head ⇔ telling truth. Since type 1 is telling truth so toss head is also true. So in case 1 result is that toss is head.
Case-2 : Let the person be type 2. Type 2 always tells lies.
So the statement "toss is head if and only if I am telling the truth" is false.
So toss head ⇔ telling truth is false. So toss head ⨁ telling truth. So toss head and telling truth have opposite truth values. Now, since type 2 telling truth is false, so toss head has to have opposite truth value which is true.
So toss head is true .So in case 2 also, result is head.
So in both cases we have proved that the result is head.
So option (a) is correct.