The correct answer is: D. No error
The sentence is grammatically correct. The conjunction “even though” is used to join two clauses that express contrasting ideas. In this case, the first clause (“He managed to make sense of the book”) expresses the idea that the person was able to understand the book, while the second clause (“even though it was the first time he read anything on the subject”) expresses the idea that the person had never read anything about the subject before. The two clauses are joined by a comma, which is the correct punctuation to use with a coordinating conjunction like “even though.”
The other options are incorrect because they suggest that there is a grammatical error in the sentence. Option A suggests that the word “he” is missing after the word “managed.” However, the word “he” is not necessary in this sentence, as it is clear from the context that the person who is speaking is referring to himself. Option B suggests that the word “even” is missing after the word “though.” However, the word “even” is not necessary in this sentence, as the word “though” already expresses the idea of contrast. Option C suggests that the word “anything” is missing after the word “read.” However, the word “anything” is not necessary in this sentence, as it is clear from the context that the person did not read anything about the subject before.