The coefficient of average rolling friction of a road is fr and its grade is +G%. If the grade of this road is doubled, what will be the percentage change in the braking distance (for the design vehicle to come to a stop) measured along the horizontal (assume all other parameters are kept unchanged?

• A. \(\frac{{0.02G}}{{{f_r} + 0.01G}} \times 100\)
• B. \(\frac{{{f_r}}}{{{f_r} + 0.02G}} \times 100\)
• C. \(\frac{{{f_r}}}{{{f_r} + 0.01G}} \times 100\)
• D. \(\frac{{0.01G}}{{{f_r} + 0.02G}} \times 100\)