Answer:
C.
Step-by-step explanation:
Given,
Initial distance Marika covered = 100 yards,
Also, She gradually increases her distance by 4 yards,
Thus, the difference between the distance of consecutive days is 4 yards,
So, there is an AP that shows the given situation,
Having first term, a = 100,
Common difference, d = 4,
Since, the explicit formula of an AP is,
Which is the required formula.
Option 'C' is correct.