Hello!
The correct answer to your question is C: capture the attention of the reader.
If your introduction cannot grasp a reader's attention, it is unlikely that he/she will be interested in reading the rest of the essay. The introduction usually includes a question, an interesting fact, etc. that may interest the reader. Without a strong introduction, your reader may find the essay to be boring and incomplete.
I hope this helps you! Feel free to comment or PM me if you have any further questions on the topic!