A male child of 15 years with a mental age of 9 years has an IQ of –

**Core Concept**
The question is testing the concept of Intelligence Quotient (IQ) and its calculation, specifically the formula for determining the IQ of an individual based on their mental age and chronological age.

**Why the Correct Answer is Right**
The formula for calculating IQ is: IQ = (Mental Age / Chronological Age) x 100. In this case, the child's mental age is 9 years and chronological age is 15 years. Plugging these values into the formula, we get: IQ = (9 / 15) x 100 = 60. This means that the child's IQ is 60, indicating that he has a developmental delay or intellectual disability.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the formula for calculating IQ is (Mental Age / Chronological Age) x 100, not (Chronological Age / Mental Age).
**Option B:** This option is incorrect because it would result in a negative IQ, which is not a valid score.
**Option C:** This option is incorrect because it would result in a score that is higher than 100, which is not possible.

**Clinical Pearl / High-Yield Fact**
A key concept to remember is that IQ scores are not always a perfect measure of an individual's intelligence, as they can be influenced by various factors such as education, socio-economic status, and access to resources. However, they can provide a useful estimate of cognitive development and potential.

**Correct Answer: D. 60**