Linear Algebra

A homogeneous system of linear equations $A x = 0$ with $n$ variables has non-trivial solutions if and only if:

Options:

• (A) $\text{rank}(A) < n$
• (B) $\text{rank}(A) = n$
• (C) $\det(A) \neq 0$
• (D) $A$ is identity