Which molecule will cross a lipid bilayer quicker?

Speed of transport across a lipid bilayer is based on two main things:

1. The size: the smaller a molecule is, the faster and more readily it will cross (B and D are bigger)
2. The charge: lipid bilayers are nonpolar, so any charged particles will have a tough time crossing the barrier, and polar molecules will have a difficult time as well. (B is charged, water is polar, but we know it moves readily through membranes)

With this in mind, it would be difficult to determine the answer between A and C

However, in the case of this question, there is one more thing to consider, which is the equation.  Since for every turn of the reaction, 2 H2O is produced for every O2 molecule, at equilibrium, it is twice as abundant, which means that most likely it is moved out of the cell more quickly to maintain homeostasis.