**Core Concept**
Intelligence Quotient (IQ) is a measure of cognitive abilities, and it is often used to assess mental age in children. The Wechsler Intelligence Scale for Children (WISC) is a standardized tool used to assess cognitive abilities in children aged 6-16 years. The scale is divided into subtests that assess verbal comprehension, visual-spatial skills, and working memory.

**Why the Correct Answer is Right**
An IQ of 50 corresponds to a mental age of 6-7 years. Children with an IQ of 50 can typically perform tasks that are expected of a 6-7 year old child, such as dressing and undressing, using utensils, and using simple language. They may also be able to perform simple arithmetic operations, such as counting and basic addition and subtraction.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because children with an IQ of 50 are not expected to perform tasks that require complex problem-solving or abstract thinking, such as operating a computer or using a smartphone.
**Option B:** This option is incorrect because children with an IQ of 50 may not be able to perform tasks that require advanced reading skills, such as reading a book or newspaper.
**Option C:** This option is incorrect because children with an IQ of 50 may not be able to perform tasks that require advanced mathematical skills, such as solving algebraic equations or calculating change.

**Clinical Pearl / High-Yield Fact**
Children with intellectual disability (IQ < 70) may have difficulty with adaptive behaviors, such as self-care, communication, and social skills. The severity of intellectual disability can be classified as mild (IQ 50-69), moderate (IQ 35-49), severe (IQ 20-34), or profound (IQ < 20). **Correct Answer: D.** Using utensils.