**Core Concept**
M-CHAT (Modified Checklist for Autism in Toddlers) is a validated screening tool designed to identify early signs of Autism Spectrum Disorder (ASD) in toddlers aged 16 to 30 months. It assesses the presence of red flags for autism, such as social and communication impairments, and repetitive behaviors.

**Why the Correct Answer is Right**
The M-CHAT evaluates various developmental milestones, including social interaction, communication, and play skills. It consists of 23 items that parents or caregivers complete to indicate whether their child exhibits behaviors that are characteristic of autism. The tool helps to identify children who may require further evaluation by a specialist, such as a psychologist or pediatrician. By using the M-CHAT, healthcare providers can initiate early intervention and support services for children with autism.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the M-CHAT is specifically designed for toddlers, not for older children or adults.
**Option B:** This option is incorrect because the M-CHAT is not a diagnostic tool for other neurodevelopmental disorders, such as ADHD or cerebral palsy.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that early detection and intervention are critical for children with autism. The M-CHAT is a valuable tool in this process, allowing healthcare providers to identify potential autism red flags and provide timely support and services.

**Correct Answer: D. M-CHAT (Modified Checklist for Autism in Toddlers)**