From the principle of mass conservation in a chemical process, the total mass of the reactants should be the same as the total mass of the products. So, the best answer here would be the first statement.
This is entirely theoretical as photosynthesis is neither a completely efficient process nor does it take place in an isolated system.
The second statement is incorrect since the products of photosynthesis are glucose and oxygen gas, which are completely different compounds from the water and carbon dioxide reactants.
The third statement is incorrect not only because it contradicts the principle of mass conservation, but because—if anything—mass is lost in the course of an inefficient chemical process like photosynthesis in the form of energy wasted as heat.
The last statement is incorrect for the same reason as the second statement is incorrect; the products are completely different substances from the reactants. For example, one of the products—glucose—can undergo combustion. One of the reactants, water, cannot combust.
