there are no choices of statements
1 significant figure, because there is no decimal after the zero the zero doesn't count.
Letter d, because they are both alkali metals (group one)
Explanation:
what you have to do is to multiply the given grams with the ratio of grams of that certain element in it's full compound in order to isolate the compound and get the element.
because the question did not specify how many grams of NO2 is formed, we can assume that the mass is neglegible, thus 1 mole was assigned to Nitrogen.