Let X = Red Blood Cell (RBC) Count in Millions $\mu$

Multiple Choice

Let x = red blood cell (RBC) count in millions per cubic millimeter of whole blood. Suppose for healthy females, x has an approximately normal distribution with mean $\mu$ = 4.9 and standard deviation $\sigma$ =0.5 Convert the following x interval from a laboratory test to a z interval. 6.9 < x

A) 1 > z
B) 4 > z
C) 4 < z
D) -4 > z
E) -1 > z