**Core Concept**
The Disabilities Act of 1995 is a legislation that aims to provide equal opportunities and protection to individuals with disabilities in India. The Act categorizes disabilities into seven categories.

**Why the Correct Answer is Right**
The correct answer refers to the seventh category of disabilities as defined by the Act. According to the Act, the seven categories of disabilities are: visual impairment, hearing impairment, locomotor disability, mental retardation, mental illness, leprosy cured, and cerebral palsy. The seventh category is usually referred to as cerebral palsy, which is a group of permanent disorders that appear in early childhood, characterized by impaired muscle tone, posture, and movement.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it is not one of the seven categories of disabilities defined by the Act.
* **Option B:** This option is incorrect as it is not the correct seventh category of disabilities.
* **Option D:** This option is incorrect as it is not one of the seven categories of disabilities defined by the Act.

**Clinical Pearl / High-Yield Fact**
It is essential for medical professionals to be aware of the categories of disabilities as defined by the Disabilities Act 1995 to provide appropriate care and support to individuals with disabilities.

**Correct Answer: C. Cerebral palsy**