Question 1103112
The test statistic is z=(x-mean)/sigma/sqrt(n)
One sided test.
a is (72-60)/20/sqrt(25), which is 12*5/20=+3,  p-value 0.0013
b is (68-60)/4, which is 2, p-value is 0.0027
c is 4/4 which is 1, and p-value is 0.1587.

As the difference between the test value and the mean decreases, the p-value increases, meaning the likelihood of such occurring as a chance value or as if the sampled population is more likely to have occurred from the postulated population.