The correct option is B 1
Mulitplicative identity refers to a number which, when multiplied with given a number, results in the given number itself.
For example, if the multiplicative identity is x, then the product of x and any number, say a, should be equal to a.
i.e., x×a=a
⇒x=1
Or, we could say that 1 is the multiplicative identity, because the product of any number and 1 is that number itself.