The expression in D evaluates to 30+4 = 34, not 10·7 = 70.
In A, (4 + 3) is equivalent to (3 + 4) by the commutative property of addition. The commutative properties of multiplication and addition allow you to swap the order of the operands with no effect on the result.
In B, 10·3 +10·4 is equivalent to 10·(3+4) by the distributive property of multiplication over addition.
In C, (3+4)·10 is equivalent to 10·(3+4) by the commutative property of multiplication.
