**Core Concept**
The evaluation of intellectual ability in a 3-year-old child requires a developmental assessment tool that can accommodate their unique cognitive, social, and emotional characteristics. This assessment should be play-based, engaging, and non-threatening to ensure accurate and reliable results.

**Why the Correct Answer is Right**
The Bayley Scales of Infant and Toddler Development (BSITD) is a standardized, norm-referenced assessment tool designed for infants and toddlers aged 1-42 months. It evaluates various aspects of development, including cognitive, language, motor, and social-emotional skills. The BSITD is particularly suitable for 3-year-olds as it assesses their problem-solving skills, memory, and ability to follow directions, providing a comprehensive picture of their intellectual ability.

**Why Each Wrong Option is Incorrect**
**Option A:** The Wechsler Preschool and Primary Scale of Intelligence (WPPSI) is a widely used assessment tool for children aged 2-7 years. However, it is primarily designed for children around the age of 5, making it less suitable for 3-year-olds.
**Option B:** The Cattell Infant Intelligence Scale is a non-standardized, non-norm-referenced assessment tool that was introduced in the 1920s. Its use is not recommended for evaluating intellectual ability in modern clinical settings.
**Option C:** The Stanford-Binet Intelligence Scale is a widely used assessment tool for children and adults. However, its administration and interpretation require extensive training and expertise, making it less suitable for a child psychologist evaluating a 3-year-old.

**Clinical Pearl / High-Yield Fact**
When assessing intellectual ability in young children, it's essential to consider the importance of developmental context and the role of play-based assessments in providing a comprehensive picture of their cognitive, social, and emotional development.

**Correct Answer:** C. Stanford-Binet Intelligence Scale