Which of These Observations Did Darwin Apply to Organisms in Nature

Which of these observations did Darwin apply to organisms in nature?

A) Malthus's observation that England's population was growing much faster than the country's agricultural capacity
B) Malthus's observation that simple organisms evolved into more complex ones, moving up the ladder of life
C) Lamarck's observation that simple organisms evolved into more complex ones, moving up the ladder of life
D) Lamarck's observation that England's population was growing much faster than the country's agricultural capacity