The element having the same valence are located in same group of periodic table
V₁=4.8 l
c₁=2.5 moles/l
c₀=6.0 moles/l
v₀-?
v(H₂O)-?
n(H₂SO₄)=v₁c₁=v₀c₀
v₀=v₁c₁/c₀
v₀=4.8·2.5/6=2.0 l
v(H₂O)=v₁-v₀
v(H₂O)=4,8-2.0=2.8 l
you need to take 2.0 liters of solution (6.0 M H₂SO₄) and 2.8 liters of water
The answer to your question is,
D) Dinitrogen trioxide
-Mabel <3