What is this expression in simplified form?

To simplify the expression ( 64sqrt{50} ), we first simplify ( sqrt{50} ).

1. Break down ( sqrt{50} ):

[

sqrt{50} = sqrt{25 times 2} = sqrt{25} times sqrt{2} = 5sqrt{2}

]

2. Substituting back into the expression:

[

64sqrt{50} = 64 times 5sqrt{2} = 320sqrt{2}

]

Thus, the simplified form of the expression ( 64sqrt{50} ) is ( 320sqrt{2} ).

So, the answer is D. 320√2.