In primary dentition, what is the most general/common occlusal relationship?

The FLUSH TERMINAL PLANE (straight/vertical distal plane — upper and lower second primary molars have their distal surfaces in the same vertical plane) is the MOST COMMON molar relationship in primary dentition, occurring in approximately 43-50% of children. Mesial step (~33%) is also common and favorable for Class I permanent occlusion. Distal step (~15%) leads to Class II. Edge-to-edge is less common. Flush terminal plane is the most prevalent. A is correct.