Meal worm experiment puzzle

Some experimenters wanted to test the response of meal worms to light and moisture.  To do this they set up four boxes, as shown in the sketch below.  They used lamps for light sources and constantly watered pieces of paper in the boxes for moisture.  In the center of each box they placed 20 meal worms.  One day later they located and counted the number of meal worms at the different locations in the boxes. They found the meal worms had crawled to the different locations in the boxes and recorded the results as below:

mealworm image

The diagrams show that meal worms respond to (respond means move toward or away from):

  1. Light but not moisture
  2. Moisture but not light
  3. Both light and moisture
  4. Neither light nor moisture

Explain your choice.