Answer:
Option A) reject null hypothesis if z is greater than 1.645
Step-by-step explanation:
We are given the following in the question: 
Sample size, n = 250
p = 30% = 0.3
Alpha, α = 0.05 
Number of women belonging to union , x = 75
First, we design the null and the alternate hypothesis 
 
This is a one-tailed(right) test.
Rejection Region:

So, the rejection region will be

That is we will reject the null hypothesis if the calculated z-statistic is greater than 1.645
Option A) reject null hypothesis if z is greater than 1.645