## Core Concept
The question pertains to the developmental milestones in infants, specifically the sequence of attainment of certain physical skills. Understanding the typical sequence and timing of these milestones is crucial for pediatricians to assess infant development.

## Why the Correct Answer is Right
The correct sequence of milestones is based on the typical developmental progression in infants.
- **Sitting without support** usually occurs around 6 to 7 months of age.
- **Crawling** typically starts around 7 to 10 months of age.
- **Standing with support** often begins around 9 to 12 months of age.
- **Walking independently** usually happens by 12 to 14 months of age.

Given these age ranges, the sequence that reflects a typical developmental progression is: sitting without support, crawling, standing with support, and then walking independently.

## Why Each Wrong Option is Incorrect
- **Option A:** This option suggests a sequence that does not align with known developmental milestones (e.g., walking before sitting).
- **Option B:** This sequence might seem plausible but does not correctly order the milestones according to typical developmental timelines (e.g., crawling before standing with support is correct, but the overall sequence may not match).
- **Option D:** This option implies a sequence where standing with support and walking independently are swapped or out of order with other milestones, which contradicts the standard developmental progression.

## Clinical Pearl / High-Yield Fact
A key point to remember is that while there is a range of normal for achieving developmental milestones, significant delays or the absence of certain milestones by specific ages can indicate developmental disorders. For instance, by 12 months, most infants should be standing with support and starting to walk independently, and by 18 months, they should be walking independently.

## Correct Answer: .