The World Wildlife Foundation Recently Reports That the Number of Monarch

The World Wildlife Foundation recently reports that the number of monarch butterflies overwintering in Mexico has declined drastically. Although extreme drought conditions have dried up nectar plants monarch butterflies rely on for food. The destruction of their overwintering grounds also poses a considerate threat. Oyamel fir trees provide shelter to monarch butterflies they are also essential to the communities that surround the forests. In the past, residents used the wood for cooking and heating, but recently, they have began to sell it in order to support their livelihoods. As a result of logging oyamel fir trees, the habitat of the monarch butterfly population has shrunk.
Other than deforestation, what other environmental issue could be causing the decline in the monarch butterfly population?

A) Air pollution from expanding population centers.
B) A prolonged drought.
C) An extended growing season brought on by heavy rain.
D) Warmer temperatures throughout the winter months.