Step 1: Understanding the Concept:
The question asks about the developmental milestone when an infant can reliably recognize their mother.
Step 2: Detailed Explanation:
A baby's ability to recognize their mother develops progressively.
From birth: Babies can recognize their mother's scent and voice.
By 2-3 months: Their vision improves significantly, allowing them to distinguish between faces. They begin to show clear signs of recognizing their primary caregivers, especially their mother, and may offer a "social smile" in response.
By 6, 8, or 10 months, this ability is well-established, but the process of clear visual recognition typically begins around the 2-3 month mark. Among the given options, 3 months is the most appropriate answer.
Step 3: Final Answer:
Babies generally begin to show clear signs of visually recognizing their mother by around 3 months of age.