Answer:
History interests me. I decided to read the Declaration of Independence.
Step-by-step explanation:
Sentence variety refers to the reduction of repetition in a text. What's also important is that it adds emphasis to important points in the text.
The first two options are somewhat repetitive as they begin with the same subject - I. The second option is additionally incorrect because there's a change in meaning compared to the original sentences.
The last two options are better because the reduction of repetition is present. Instead of I, the subject in the first sentence is history. The fourth option is not the best because the second sentence is redundant. That leaves us with the third option as the best one.