Which of the following probabilities is the greatest for a standard normal distribution? a. p(-1.5≤z≤-0.5) b. p(-0.5≤z≤0.5) c. p(0.5≤z≤1.5) d. p(1.5≤z≤2.5)

All intervals are 1 unit long. You just have to look at the picture of normal distribution ( look at the attachment) and look which interval covers the most area.

You will see that p(-0.5<z<0.5) is the one that covers 34% of area, meaning the probability is 34%. All the other intervals are much less than 34%.