For a series $S = 1 - 2 + 3 - 4 + \dots$ up to $n$ terms,
Statement-$1$: The sum of the series is always dependent on the value of $n$,i.e.,whether it is even or odd.
Statement-$2$: The sum of the series is $-\frac{n}{2}$ when the value of $n$ is any even integer.

• A
  Statement-$1$ is true,Statement-$2$ is true,but Statement-$1$ is not the correct explanation for Statement-$2$.
• B
  Statement-$1$ is true,Statement-$2$ is false.
• C
  Statement-$1$ is false,Statement-$2$ is true.
• D
  Both statements are true,and Statement-$1$ is the correct explanation of Statement-$2$.