The operation \nabla is defined by g\nabla h=g^2-h^2. For example, 2\nabla1=2^2-1^2=3. If g>0 and g\nabla6=45, the value of g is

**Answer Choices**

A. 39

B. 6

C. 81

D. 3

E. 9

The operation \nabla is defined by g\nabla h=g^2-h^2. For example, 2\nabla1=2^2-1^2=3. If g>0 and g\nabla6=45, the value of g is

**Answer Choices**

A. 39

B. 6

C. 81

D. 3

E. 9