Question

"Plants are able to continue to grow and develop once the starch supply in the seed is gone, because they

Answer 1

While the seed is germinating, it uses the stored starch in the cotyledons as a source of energy, but with time, the stored reserve is depleted. After the starch supply in the seed is gone, the plant still continues growing because it contain chloroplasts. The chloroplasts are a type of plastids and are a site for photosynthesis. The light energy from the sun is converted into chemical energy in the chloroplasts, which help the plant to continue growing.

Hence, the correct answer is option (c) - 'have chloroplast and use light energy to make more food'.

Answer 2

I am pretty sure that plants are able to continue to grow and develop once the starch supply in the seed is gone, because they have chloroplasts and use light energy to make more food. I consider third option to be correct one as it does contain the most essential points to developing. It cathes sunlight due to the photosynthesis which is made of hloroplasts. 
That will definitely help you!