Which relation is a linear function with the greatest slope?

The one you answered is correct. It is infinitely steep

A = $ 861.69

Equation:
A = P(1 + rt)
Calculation:
First, converting R percent to r a decimal
r = R/100 = 5.5%/100 = 0.055 per year,
putting time into years for simplicity,
1 quarters ÷ 4 quarters/year = 0.25 years,
then, solving our equation

A = 850(1 + (0.055 × 0.25)) = 861.6875 
A = $ 861.69

The total amount accrued, principal plus interest,
from simple interest on a principal of $ 850.00
at a rate of 5.5% per year
for 0.25 years (1 quarters) is $ 861.69.