If a matrix has 7 elements, then it can be a
(A) Scalar matrix
(B) Symmetric matrix
(C) Column matrix
(D) Row matrix
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (C) and (D) only
A matrix of order m × n has mn elements. Since 7 is prime, mn = 7 allows only 1 × 7 and 7 × 1.
So a matrix with 7 elements is either 1 × 7 (a row matrix) or 7 × 1 (a column matrix), and it is never square.
Checking the statements
(A) Scalar matrix — Incorrect. A scalar matrix is square, and 7 is not a perfect square.
(B) Symmetric matrix — Incorrect. A symmetric matrix must also be square.
(C) Column matrix — Correct. A 7 × 1 matrix has 7 elements.
(D) Row matrix — Correct. A 1 × 7 matrix has 7 elements.