Heat of combustion is a chemical property that can be measured.
The answer for your question is D
There are two isotopes of uranium abundant in nature
U235 and U238
As given that the sample has average molar mass of 237.482 amu
Let the amount of U235 in 100g sample = x
the amount of U238 in 100 g sample = 100-x
the average molar mass = [235(x) + 238 (100-x)] / 100
237.482 = [235(x) + 238 (100-x)] / 100
237.482 X 100 = [235(x) + 238 (100-x)]
23748.2 = 235 x + 23800 - 238x
51.8 = 3x
x = 17.27 g
So percentage of U-235 = 17.27 %
sorry but I need some three point so that's why I didn't