If `a`, `b` and `c` are all different from zero, such that `1/a+1/b+1/c=0`, then the matrix
`A=[(1+a,1,1),(1,1+b,1),(1,1,1+c)]` is

Options

A. symmetric
B. non-singular
C. can be written as sum of a symmetric and a skew symmetric matrix
D. none of these