A. A lunatic who is prevented by his lunacy from understanding the questions put to him
The answer is: A
Explanation
The correct option is A: A alone.
According to Section 118 of the Indian Evidence Act, 1872, all persons are competent to testify unless they are prevented from understanding the questions put to them or from giving rational answers to those questions by any cause of the same kind as tender years, extreme old age, disease, whether of body or mind, etc.
Therefore, the following persons are competent to testify:
- A child above 7 years but below 12 years able to exhibit maturity and understanding. The age of the child is not a bar to his competency, as long as he can give a rational testimony.
- A dumb person capable of putting things in writing. The mode of communication is not a factor affecting the competency, as long as the person can understand the questions and give rational answers.
- A witness who is related to the deceased. The relationship of the witness with the deceased is not a ground for disqualification, as long as the witness is not biased or interested in the outcome of the case.
The only person who is not competent to testify is:
- A lunatic who is prevented by his lunacy from understanding the questions put to him. The mental condition of the person is a valid reason for excluding him from testifying, as he cannot give a reliable or coherent evidence.