a. Sorry if you picked "a". The element neon, Ne, is a nonmetal and a noble gas. The elements in group 8A are unreactive. The rule that says nonmetal group number minus 8 predicts the negative charge gives a charge of zero. 8 - 8 = 0 Clearly this is not a +1.
b. Sorry if you picked "b" iodine. The element iodine, I, is a nonmetal. It is in group 7A. The elements in group 7A have seven outer electrons in the subshells ns2np5. There is room for one more electron in this subshell set. The rule of group number minus 8 predicts a charge of minus one. 7 - 8 = -1
c. Sorry if you picked "c" strontium. Strontium is in group 2A. It has two outer or valence electrons. These two electrons can be removed relatively easily. The cation has a charge of +2 just like calcium.
d. Great, lithium is in group 1A. It has one outer or valence electron. This electron can be removed relatively easily. The lithium cation has a charge of +1 just like sodium. The general rule is that the alkali metals in group 1A form cations with a charge of +1.