Four numbers are chosen at random (without replacement) from the set $\{1, 2, 3, ..., 20\}$. Statement-1 : The probability that the chosen numbers when arranged in some order will form an AP is $\frac{1}{85}$. <br> Statement-2 : If the four chosen numbers from an AP, then the set of all possible values of common difference is $\{ \pm1, \pm 2, \pm 3, \pm 4, \pm 5 \}$.

Question

( A ) Statement-1 is true, Statement-2 is true; Statement-2 is the correct explanation for Statement-1
( B ) Statement-1 is true, Statement-2 is true; Statement-2 is not the correct explanation for Statement-1
( C ) Statement -1 is true, Statement-2 is false
( D ) Statement -1 is false, Statement-2 is true