The correct answer is A
As the name suggests, we distribute the multiplier over the terms in the parenthesis that are adding.
The distributive property of multiplication over addition simply says that, if a number is multiplying the whole parenthesis with the terms inside the parenthesis adding, multiply each of the terms by the number and add them.
[tex]a\times(b+c)=a\times b+ a\times c[/tex]
Comparing this property to the above options, it is only in option A that the distributive of multiplication over addition has been used.
Note however that, addition is not distributive over multiplication.