The answer for the exercise is the third option, which is: Hexagon.
The explanation is shown below:
As you can see in the figure attached, the cross section is a polygon of six sides and six angles. Therefore, it has six vertexes. In geometry, this type of polygon is known as "Hexagon".
During a week:
Kevin works 3z during 5 days
kevin work (4z-7) during 1 day.
Kevin work 0 during 1 day.
z=unit time
f(z)= number of hours kevin works in one week.
f(z)=5(3z)+(4z-7)+0
f(z)=15z+4z-7
f(z)=19z-7
The number of hours kevin woirs in one week in terms of z is:
f(z)=19z-7