**Core Concept**
The question is testing the developmental milestone of drawing a cross, a task that reflects the child's fine motor skills and cognitive abilities. This milestone is an indicator of a child's neurological development, specifically the maturation of the brain's motor and cognitive centers.

**Why the Correct Answer is Right**
Drawing a cross requires the child to have developed sufficient fine motor skills to hold a pencil or crayon and to have the cognitive ability to understand the concept of a cross. This typically occurs around the age of 5-6 years, when children's brains have matured enough to coordinate hand movements and demonstrate an understanding of spatial relationships. The ability to draw a cross also indicates that the child has developed sufficient hand-eye coordination and dexterity to manipulate a writing instrument.

**Why Each Wrong Option is Incorrect**
* **Option A:** Drawing a circle is a more basic fine motor task that is typically achieved earlier, around 3-4 years of age. It does not require the same level of cognitive understanding as drawing a cross.
* **Option B:** Drawing a square is a more complex shape than a cross, and is typically achieved later, around 7-8 years of age. It requires a higher level of fine motor skills and cognitive understanding than drawing a cross.
* **Option C:** Drawing a stick figure is a more basic representation of a person and is typically achieved earlier, around 4-5 years of age. It does not require the same level of fine motor skills or cognitive understanding as drawing a cross.

**Clinical Pearl / High-Yield Fact**
Delayed development of fine motor skills, including drawing a cross, can be an indicator of underlying neurological or developmental disorders, such as cerebral palsy or autism spectrum disorder. Therefore, it is essential to assess a child's fine motor skills and cognitive abilities as part of their overall developmental evaluation.

**Correct Answer: B. 7-8 years.**