The Following Information Was Obtained from Matched Samples Taken from Two

The following information was obtained from matched samples taken from two populations.Assume the population of differences is normally distributed. $\begin{array}{lll}\text { Individual } & \text { Method 1 } & \text { Method 2 } \\1 & 7 & 5 \\2 & 5 & 9 \\3 & 6 & 8 \\4 & 7 & 7 \\5 & 5 & 6\end{array}$
The null hypothesis tested is H₀: $\mu$ d = 0.The test statistic for the difference between the two population means is

A) 2.
B) 0.
C) -1.
D) -2.