Answer: A. 1.2
Step-by-step explanation:
Given : Sample size : n= 64
Standard deviation: 
The formula to find the standard error of mean is given by :-

Therefore, the standard error of the mean= 1.2
Hence, A is the right option.
For one moth it would be....

$57.00 In total but im not sure if this is correct so if you could make sure please.
It would be 28-10=x because your ending up with 28 after earning 10 you would get that. Hope this works!
Yeah Thanks I love to see that and the answer A