If the function assumes a is multiplied by b, where a = 6 and b = 4, this means the result is 24. We won't change the value result, so if b was multiplied by 4, we need to find 16/4 and this is also 4, so when we multiply this value with 6, it's once again 24. Therefore, the answer is 24. The other options are inaccurate.