The correct answer is: D. No error
The sentence is grammatically correct. The first clause, “It does not matter how you do it,” is an independent clause. The second clause, “what I want is that you should finish the work within a month,” is a dependent clause. The dependent clause is introduced by the subordinating conjunction “that.” The two clauses are joined by a semicolon, which is used to join two independent clauses that are closely related in meaning.
The sentence is clear and concise. The meaning of the sentence is easy to understand. The sentence is also well-organized. The ideas are presented in a logical order.
The sentence is also free of errors in grammar, punctuation, and spelling.