There are mainly two types of steering system:

Davis steering gear:

• A Davis steering gear has sliding pair which means more friction and easy wearing.
• The gear fulfills the fundamental equation of gearing in all positions.
• However, due to easy wearing it becomes inaccurate after some time.

Ackermann steering gear: 

• An Ackermann steering gear has only turning pairs thus is preferred.
• Its drawback is that it fulfills the fundamental equation of correct gearing at the middle and the two extreme positions and not in all positions. 

Hence, the correct option is (A).