**Core Concept**
The question is testing the developmental milestones of an 8-month-old baby. At this stage, babies typically exhibit significant improvements in gross motor skills, including sitting, standing, and walking. The correct answer will reflect a skill that is within the normal range of development for an 8-month-old baby.

**Why the Correct Answer is Right**
At 8 months, babies usually start to pull themselves up to a standing position while holding onto furniture or a person's hand. This is a major milestone in gross motor development, indicating improvements in strength, balance, and coordination. The ability to pull oneself up to a standing position is a precursor to independent walking.

**Why Each Wrong Option is Incorrect**
**Option A:** Sitting up unassisted - While 8-month-old babies can sit up unassisted, this skill is typically mastered earlier, around 6-7 months.
**Option B:** Crawling - Crawling is a skill that is often mastered between 7-10 months, so it is still within the normal range of development for an 8-month-old baby.
**Option C:** Walking independently - Walking independently is typically mastered around 12-14 months, so it is not within the normal range of development for an 8-month-old baby.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that developmental milestones can vary significantly among babies, and some may need to be reassessed if there are concerns about their development. The American Academy of Pediatrics recommends regular check-ups to monitor development and address any concerns.

**Correct Answer: B. Crawling.**