Solve: (5×6×4)^x × 3^x × 4^y Exponential Expression

First, let's calculate the result of the multiplication inside the parentheses in the first term of the multiplication and write down the entire expression:

$(5\cdot6\cdot4)^x\cdot3^x\cdot4^y=120^x\cdot3^x\cdot4^y$
Now we notice that the first two terms in the multiplication have the same exponent, so we can use the law of exponents for parentheses, but in the opposite direction:

$z^n\cdot t^n=(z\cdot t)^n$
This means that instead of opening the parentheses while applying the (same) exponent to each term of the multiplication inside the parentheses, we'll put the two terms (with identical exponents) as a multiplication in parentheses under the exponent. This is possible in this problem because the first two terms in the multiplication have identical exponents,

Let's apply it to the problem:

$120^x\cdot3^x\cdot4^y =(120\cdot3)^x\cdot4^y$
Now we can of course calculate the result of the multiplication inside the parentheses if we want, and simplify the resulting expression even further, but at this stage it's worth noting that this result is answer A, and there is no other answer among the options that is both correct and more simplified,

Therefore, the correct answer is A.