If the order of the matrix is m×n, then how many elements will there be in the matrix?

The correct option is mn.

Step-by-step Explanation:

A matrix is a rectangular arrangement of numbers, symbols, or expressions in rows and columns. The size, dimension, or order of a matrix is commonly represented as:

$$m\times n$$

Here, the order is defined by two variables:

$m$
represents the number of rows in the matrix.

$n$
represents the number of columns in the matrix.

Since the matrix has
$m$
rows and each row consists of
$n$
elements (one for each column), the total number of elements is obtained by multiplying the number of rows by the number of columns:

$$\text{Total elements}=m\times n=mn$$

Thus, the matrix contains exactly mn elements.