Which effect of the weather would most likely be studied by biologists who work in this location?

Although it is not mentioned the location, I found the exercise on the internet with the following options:
A)weathering and erosion of park pathways 
B)deterioration of the man-made structures in the park 
C)pattern and timing of leaf loss in the shade trees 
D)exposure of rocks and minerals found in the soil

The only effect, out of this options, that would be studied by biologists is the "pattern and timing of leaf loss in the shade trees". This is the only effect related to life, which is the subject of biology - living organisms and their mechanisms. Leaf loss is a process undergone by many trees as colder seasons, or dry seasons in the case of trees in tropical forests, approach.