If `G` is the set of all matrices of the form `[xxxx]` , where `x in R-{0}` , then the identity element with respect to the multiplication of matrices as binary operation, is `[1 1 1 1]` (b) `[-1//2-1//2-1//2-1//2]` (c) `[1//2 1//2 1//2 1//2]` (d) `[-1-1-1-1]`

Explanation

`AE=A=>[[x, x], [x, x]][[e, e], [e, e]]=[[x, x][x, x]]`

`[[2ex, 2ex], [2ex, 2ex]]=[[x, x], [x, x]]`

`2ex=x=>x=1/2`

`e=[[1/2, 1/2], [1/2, 1/2]]`