Square matrix and diagonal matrix

The matrix A=[004040400] is a (a) square matrix (b) diagonal matrix (c) unit matrix (d) none of these

The matrix A= [[0, 0, 4] ,[0 ,4, 0] ,[4 ,0, 0]] is a (a) square matrix (b) diagonal matrix (c) unit matrix (d) none of these

Which of the following is a triangular matrix? (A) a scalar matrix (B) a lower triangular matrix (C) an upper triangular matrix (D) a diagonal matrix

Which of the following is a triangular matrix? (A) a scalar matrix (B) a lower triangular matrix (C) an upper triangular matrix (D) a diagonal matrix

The matrix A=[{:(0,0,2),(0,2,0),(2,0,0):}] is: a) scalar matrix b) diagonal matrix c) square matrix d) none of these

The inverse of a diagonal matrix is a. a diagonal matrix b. a skew symmetric matrix c. a symmetric matrix d. none of these

The inverse of a diagonal matrix is a. a diagonal matrix b. a skew symmetric matrix c. a symmetric matrix d. none of these

The inverse of a diagonal matrix is a. a diagonal matrix b. a skew symmetric matrix c. a symmetric matrix d. none of these

The inverse of a diagonal matrix is a. a diagonal matrix b. a skew symmetric matrix c. a symmetric matrix d. none of these

Consider the following statements : 1. every zero matrix is a square matrix. 2. A matrix has a numerical value. 3. A unit matrix is a diagonal matrix. Which of the above statements is/are correct ?