The correct answer is: B. 190 kg/cm2
Mild steel stirrups are used in reinforced concrete to resist tensile forces. The allowable tensile stress in mild steel stirrups is 190 kg/cm2. This means that the stirrups can withstand a tensile force of 190 kilograms per square centimeter before they fail.
The other options are incorrect because they do not represent the allowable tensile stress in mild steel stirrups. Option A is too high, option C is too low, and option D is not a valid option.
Here is a brief explanation of each option:
- Option A: 1400 kg/cm2. This is the allowable tensile stress in high-strength steel. High-strength steel is not typically used for stirrups in reinforced concrete.
- Option B: 190 kg/cm2. This is the correct answer.
- Option C: 260 kg/cm2. This is the allowable tensile stress in mild steel bars. Mild steel bars are typically used for the main reinforcement in reinforced concrete, not for stirrups.
- Option D: 230 kg/cm2. This is not a valid option.