manhattan gmat sentence correction

[resilient]

I dont understand why my answer is wrong. I chose D but correct answer is E.

The number of acres destroyed by wildfires, which have become an ongoing threat due to drought and booming population density, have increased dramatically over the past several years, prompting major concern among local politicians.

have become an ongoing threat due to drought and booming population density, have increased
have become an ongoing threat due to drought and booming population density, have been increasing
has become an ongoing threat because of drought and booming population density, has increased
have become an ongoing threat due to drought and booming population density, has increased
have become an ongoing threat because of drought and booming population density, has increased

Can anyone help!?

[simplyjat]

The difference lies in the meaning of "because of" and "due to"...

Due to means “caused by.” Due to does not mean “because of.”

- “The game was postponed do to rain.” (Incorrect)
- “The game was postponed because of rain.” (Correct)
- “The game’s postponement was due to rain.” (Correct)

[resilient]

i am so sorry. I chose C becasue the word in front "of" which is NUMBER and is a singular. SO, i used HAS. So I need to re-ask my question of why C is wrong? What is the difference between because of and due to. is because of needed with an action clause and due to paired with a noun?

[simplyjat]

The modifying phrase "which have become an ongoing threat due to drought and booming population density" is modifying wildfires, and not "the number of wildfires" and thus a plural verb.