Which expression correctly defines ρbal in terms of f′c, f_y, β1, εty, dt and d?

• A. ρbal = (0.85 f'c)/fy * β1 * (0.003/(0.003+ εty)) * (dt/d)
• B. ρbal = (0.85 f'c)/fy * β1 * (0.003+ εty)/(0.003) * (dt/d)
• C. ρbal = (0.85 f'c)/fy * β1 * (dt/d) / 0.008
• D. ρbal = (0.85 f'c)/fy * β1 * (0.003/(0.003+ εty)) / (dt/d)

Answer: (A)