Two Samples Are Selected at Random from Two Independent Normally $\bar { X } _ { 1 } - \bar { X } _ { 2 }$

Two samples are selected at random from two independent normally distributed populations. Sample 1 has 49 observations and has a mean of 10 and a standard deviation of 5. Sample 2 has 36 observations and has a mean of 12 and a standard deviation of 3. The standard error of the sampling distribution of the sample mean difference, $\bar { X } _ { 1 } - \bar { X } _ { 2 }$ , is: $\begin{array}{|l|l|}\hline\text { A. } & 0.1853 \\\hline \text { B. } & 0.7602 \\\hline \text { C. } & 0.7331 \\\hline \text { D. } & 0.8719 \\\hline\end{array}$