Answer:
The decision made by the researcher based on this information is to reject the null hypothesis.
Step-by-step explanation:
Two-tailed hypothesis test:
Critical value: 
Test statistic: z
If
, we do not reject the null hypothesis.
If
, we reject the null hypothesis.
In this question:

Since
, we reject the null hypothesis.
The decision made by the researcher based on this information is to reject the null hypothesis.
Jack needs 72 feet of fencing.
You had to do 4 ft x 18 ft which would give you the answer of 72. To find the area of a rectangle you do length x width.
I think the correct answer is b