The number of commutative binary operation on the set A = {1, 2} is ___________.

Correct option is B

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$$\text{The number of commutative binary operations on a set with } n \text{ elements is given by the formula:}\\\frac{n(n+1)}{2}\\\text{Given the set } A = \{1, 2\}, \text{ which has 2 elements:}\\\text{Number of commutative binary operations on the set } A = \frac{2(2+1)}{2} = 2^3 = 8$$​​