In the following diagram, two models of succession are represented. In this diagram A, B, C and D are species and arrows indicate 'is replaced by'

Based on the above, which statement is correct?
a. Figure 1 represents facilitation model and figure 2 represents tolerance model.

b. Figure 1 represents tolerance model and figure 2 represents facilitation model.

c. Figure 1 represents facilitation model and figure 2 represents inhibition model.

d. Figure 1 represents tolerance model and figure 2 represents inhibition model.