The value of $$6\frac{1}{5}-\left[4\frac{1}{2}-\left\{\frac{5}{6}-\left(\frac{3}{5}+\frac{3}{10}-\frac{7}{15}\right)\right\}\right]$$ is:

A

2.1

B

2.8

C

2.5

D

1.8