**Core Concept**
The question is testing the student's knowledge of the classification of intellectual disability based on IQ scores. Intellectual disability is a neurodevelopmental disorder characterized by significant impairment in cognitive functioning and adaptive behavior, affecting daily life and social interactions.

**Why the Correct Answer is Right**
The correct answer is related to the classification of intellectual disability as per the World Health Organization (WHO) and the American Psychiatric Association (APA). An IQ score of 40-54 is classified as mild intellectual disability, while a score of 35-39 is classified as moderate. A score of 20-34 is classified as severe, and below 20 is classified as profound. An IQ score of 45 falls under the category of mild intellectual disability.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely incorrect because it does not match any known classification of intellectual disability.
**Option B:** This option might be incorrect because the exact classification and IQ score ranges might not match the correct answer.
**Option C:** This option might be incorrect because the IQ score range might not be accurate for the classification mentioned.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that intellectual disability is a heterogeneous condition, and IQ scores are not the sole criteria for diagnosis. A comprehensive evaluation of cognitive, adaptive, and behavioral functioning is necessary for accurate diagnosis and classification.

**Correct Answer: B. Mild intellectual disability**