Among B₂H₆, B₃N₃H₆, N₂O, N₂O₄, H₂S₂O₃, and H₂S₂O₈, the total number of molecules containing a covalent bond between two atoms of the same kind is:
A. 9.6×10⁻²kg
B. 4.8×10⁻²kg
C. 19.2×10⁻²kg
D. 1.2×10⁻²kg