Ans : c,d
The rank of matrix is equal to the rank of transpose of a matrix.
Here Rank =2 (Using Echelon method ) . So, option a , b is eliminated .
No of linearly independent solutions =(n-r) where n is no of variable and r is rank of matrix .So, here it is 4-2=2.
So, c,d is correct and e is eliminated.
Hope it helps.