What Caused Darwin to Rush into Publication,On the Origin of Species

What caused Darwin to rush into publication,On the Origin of Species in 1859?

A) A letter he received from Alfred Russel Wallace outlined a hypothesis very similar to his own.
B) He lived in fear of being ostracized by the Church of England.
C) He was in ill health and wanted to publish his theory before he died.
D) He was deeply in debt and needed the money.
E) Darwin knew his hypothesis must be published before it could become a theory.