Step 1: Understanding the Concept:
The Indian Evidence Act, 1872, lays down the methods by which the authorship of a handwriting or signature can be proved in a court of law.
Step 2: Detailed Explanation:
The Act provides for several modes of proving handwriting, including:
1. By the opinion of an expert (Section 45): A person specially skilled in identifying handwriting (a handwriting expert) can give their opinion on whether a particular document was written or signed by a certain person.
2. By the opinion of a person acquainted with the handwriting (Section 47): A person is said to be "acquainted" if they have seen that person write, or have received documents written by that person, or have in the ordinary course of business received documents purported to be written by that person. Such a non-expert can also give an opinion.
3. By the admission of the person who wrote it.
4. By the evidence of a person who saw the document being written or signed.
5. By comparison by the court itself (Section 73).
The options (A) and (B) correspond to Sections 45 and 47 respectively, both of which are valid methods. "Police verification" is not a method of proof in court. Therefore, the correct answer is (D), which includes both (a) and (b).
Step 3: Final Answer:
Handwriting can be proved both by the opinion of experts and by the evidence of a person acquainted with the handwriting.