A square matrix A = [aᵢⱼ ]ₙₓₙ, if aᵢⱼ = 0 for i < j then that matrix is known as _______

A square matrix A = [aᵢⱼ ]ₙₓₙ, if aᵢⱼ = 0 for i < j then

1.	A square matrix A = [aᵢⱼ ]ₙₓₙ, if aᵢⱼ = 0 for i < j then that matrix is known as _______
A.	Upper triangular matrix
B.	Lower triangular matrix
C.	Unit matrix
D.	Null matrix
Answer» C. Unit matrix