In the $AP: 10, 5, 0, -5, \ldots$,the common difference $d$ is equal to $5$. Justify whether the above statement is true or false.

(B) The common difference $d$ of an $AP$ is calculated as $d = a_{n} - a_{n-1}$.
For the given $AP: 10, 5, 0, -5, \ldots$:
$a_{2} - a_{1} = 5 - 10 = -5$
$a_{3} - a_{2} = 0 - 5 = -5$
$a_{4} - a_{3} = -5 - 0 = -5$
Since the difference between consecutive terms is constant,the given list of numbers forms an $AP$ with a common difference $d = -5$.
Therefore,the statement that the common difference $d$ is equal to $5$ is false.