Determine is a solution is basic in linear system.

Question

We know that the maximum number of basic solution of a linear system is given by nCm where n is number of unknowns and m is the rank of coefficient matrix and also of augmented matrix. By setting (n-m) variables equal to zero we obtain a basic solution. But if the question gives a solution and asks to check if the solution is basic then how should I approach? Finding all the nCm basic solution and checking can be very lengthy procedure.