Answer:
The correct option is:
d = 2.5t , continuous
Explanation:
It is given that:
Jeff hiked for 2 hours and traveled 5 miles.
This means that the speed of Jeff is:

( Since speed is defined as the ratio of distance over time i.e.

i.e.
)
Also, it is given that:
He continues at the same pace.
This means that the speed remains constant over the time.
Hence, the relationship that holds between the distance(d) and time(t) is:

Since,

Also, the graph will be continuous , since the distance depends over the period of time and he will travel different distance over different time.