Hihi!
The correct answer is B. The mass number of this nuclide is 131! It's proton number is 56 and it has 75 neutrons (131 - 56 = 75 neutrons).
I hope I helped!
-Jailbaitasmr
1 3/4 Ounces or 1.75 Ounces!
Basically 21/12 = 1.75!
(Mark me as the brainliest if this helps!)
B. A gram would have a lot more molecules of propane than a mole