The proportion of $2 \times 2$ non-singular matrix whose terms are either $0$ or $1$ is

Question

Multiple Choice Question with more that one correct answer.

The proportion of $2 \times 2$ non-singular matrix whose terms are either $0$ or $1$ is

i)-$\frac{1}{2}$

ii)-$\frac{1}{4}$

iii)-$\frac{1}{8}$

iv)-$\frac{1}{16}$

No. of $2 \times 2$ matrices of determinant $0$ is $6$

So I think the answer should be $\frac{10}{16}=\frac{5}{8}$. But its not in option.

Am I wrong? Had I understood the question incorrectly?