The answer is exactly 10 grams because of the law of conservation of mass which states that for a closed system, the mass of the system must remain constant over time, hence the mass of the products formed after the reaction cannot increase nor decrease as this will violate the law stated earlier.
The above explanation proves the reason for option B. The remaining options suggest either an increase or a decrease in the mass of the product formed which is not possible.
The noble gases have 8 valence electrons in their outermost electron shell. In other words, they have full out shells. These elements are highly stable.
