A confidence interval for the average test score in a class is given as $(72.4,79.6)$. What are the sample mean and the margin of error?

$\bar{x}=76.0$   

$E=3.6$

$\bar{x}=76.0$   

$E=2.6$

$\bar{x}=75.0$   

$E=3.6$

$\bar{x}=75.0$   

$E=2.6$