Answer: a. $128.125
Step-by-step explanation:
The standard error of the mean is given by :
[tex]SE=\dfrac{\sigma}{\sqrt{n}}[/tex] , where [tex]\sigma[/tex] = population standard deviation , n= sample size.
Given: [tex]\sigma=\$2,050[/tex]
n= 256
Then, the standard error of the mean:-
[tex]SE=\dfrac{2050}{\sqrt{256}}\\\\=\dfrac{2050}{16}=\$128.125[/tex]
Hence, option a. is correct.