Two factors which cause global climate change are listed below.

Factor 1: Mountain building.

Factor 2: Changes in the amount of atmospheric gases.

Which of these statements is correct about the two factors which cause global climate change?

A. Factor 2 is a natural factor and Factor 1 is influenced only by human factors.

B. Factor 1 is a natural factor and Factor 2 is influenced only by human factors.

C. Factor 1 is a natural factor and Factor 2 may be influenced by both nature and human factors.

D. Factor 1 is a human induced factor and Factor 2 may be influenced by both nature and human factors.