Explanations:
Question 1: Lithium in 20.00+ g is C. or D., but 25.00+ g is D. which means this is the correct option.
I am unsure of Question 2. I don't think it is mole though.
Question 3: Boron in 25.00-30.00 g is B. or D., but 25.00 g would be C.
Question 4: 2.393 x 1024 atoms of Oxygen is 63.58 mole O. I don't know for sure, but I think this is correct.
I am NOT professional. There is a chance I am incorrect. Please reply to me if I've made a mistake.