Plants stores carbohydrates in the form of starch granules and use them for the primary form of metabolism, which consists of two partsamylose and amylopectin and uses them during photosynthesis.
The answer to this is D. Starch. A lot of plants would usually store extra sugar so that they will have enough and this is usually stored in the roots of the plant. Whenever a plant needs the extra energy, that is the time when starch would be transferred back to sugar once again.
Experts will know if photosynthesis occurs and exists in plants if there would be signs of starch within the plant. You can probably find starch in some of the stems and there will also be starch that can be found in the leaves of the plant. A sun-deprived plant will not have enough starch available to survive