Design speed (v) = 80 km/h = 80 × 5/18 = 22.22 m/s

To determine the required super elevation for a highway curve section, we need to consider the design lateral friction and the radius of the curve. The super elevation is the banking of the road at a curve, which helps to counteract the centrifugal force and keep vehicles on the road.

Given:
Speed limit = 80 km/h
Radius of curve = 250 m

1. Determine the Design Speed:
The design speed is usually a higher value than the speed limit to account for certain factors. In this case, let's assume the design speed is 1.2 times the speed limit.
Design speed = 1.2 * 80 km/h = 96 km/h

2. Convert the Design Speed to m/s:
Design speed = 96 km/h = 96 * (1000 m/3600 s) = 26.67 m/s

3. Calculate the Centrifugal Acceleration:
Centrifugal acceleration (ac) can be calculated using the formula:
ac = (V^2) / R
where V is the velocity in m/s and R is the radius in meters.
ac = (26.67^2) / 250 = 2.8456 m/s^2

4. Determine the Required Super Elevation:
The required super elevation (e) can be calculated using the formula:
e = ac / g
where g is the acceleration due to gravity (9.81 m/s^2).
e = 2.8456 / 9.81 = 0.2902

5. Convert the Required Super Elevation to a Percentage:
The super elevation is usually expressed as a percentage. To convert it, we multiply by 100.
Required super elevation = 0.2902 * 100 = 29.02%

However, the question asks for the answer in terms of super elevation ratio (e/H), where H is the lane width. The super elevation ratio can be calculated using the formula:
e/H = tan(α)
where α is the angle of the road surface with the horizontal.

6. Determine the Super Elevation Ratio:
Assuming a standard lane width of 3.5 meters, we can calculate the super elevation ratio using the given radius.
e/H = tan(α)
e/3.5 = tan(α)
α = tan^(-1)(e/3.5)
α = tan^(-1)(0.2902/3.5) = 0.082 radians

7. Convert the Super Elevation Ratio to a Percentage:
To convert the super elevation ratio to a percentage, we multiply by 100.
Super elevation ratio = 0.082 * 100 = 8.2%

Therefore, the required super elevation for the given curve section is approximately 8.2%, which corresponds to option C in the answer choices.