**Core Concept**
Infants develop gross motor skills at a rapid pace during the first year, progressing from reflexive movements to purposeful actions. By 7 months, infants exhibit various motor milestones, including transferring objects, pivoting, and enjoying mirror reflections, which are essential components of their cognitive and motor development.

**Why the Correct Answer is Right**
Cruising, or moving along a stable object like a couch or chair for support, typically begins around 9-12 months of age. This activity requires a higher level of balance, coordination, and strength than what a 7-month-old infant possesses. At 7 months, infants are still refining their ability to sit up, transfer objects, and pivot, indicating that they are not yet ready for cruising.

**Why Each Wrong Option is Incorrect**
**Option A:** Pivoting is a skill that develops around 7 months, where infants learn to turn their bodies while keeping their feet on the ground, a precursor to walking.
**Option C:** Transferring objects is a fundamental skill that infants develop around 6-7 months, as they practice moving toys or objects from one hand to another.
**Option D:** Enjoying mirror reflections is a cognitive milestone that occurs around 6-12 months, where infants begin to recognize and respond to their own reflections.

**Clinical Pearl / High-Yield Fact**
Infants typically develop gross motor skills in a predictable sequence, and parents can use these milestones as an indicator of normal development. By 7 months, infants should be able to sit up without support, transfer objects from one hand to another, and pivot while keeping their feet on the ground.

**✓ Correct Answer: B. Cruise**