I think the correct answer would be the first option. When a solution of LiC2H3O2 is mixed with a solution of MgSO4, no reaction would be observed from the mixture. This is because magnesium cannot replace lithium from the acetate compound. Lithium is the least reactive substance based from the activity series. So, it can only react with a few substances and it does involve the reaction with magnesium sulfate. It is the very least reactive of all the alkali metals.