What is the phenomenon that is causing the bean seedling to bend as shown? O gravitropism
O phototropism
O rapid response
O thigmotropism

The answer is B. phototropism.

Phototropism is the orientation of a plant or other organism in response to light, either toward the source of light ( positive phototropism ) or away from it ( negative phototropism ).

So as we can see here the seedling is bending towards the sunlight, which is positive phototropism