Which sentence corrects the dangling modifier in the sample sentence?

After reading the whole book, the ending was unsatisfying.

Reading the whole book, the ending was unsatisfying.
After reading the whole book, I found that the ending was unsatisfying.
After reading the whole book, the ending became unsatisfying.
Reading the whole book, the ending was unsatisfying.

b because it makes the most sense

The correct sentence that correctly corrects the dangling modifier in the sample sentence is: "After reading the whole book, I found that the ending was unsatisfying."

Explanation:
In the original sentence, "After reading the whole book, the ending was unsatisfying," there is a dangling modifier. The phrase "After reading the whole book" is intended to modify the subject of the sentence, but it is not clear what that subject is. The sentence does not clearly state who is doing the reading.

To correct the dangling modifier, we need to include a subject before the modifying phrase that makes it clear who is doing the reading. In the correct answer "After reading the whole book, I found that the ending was unsatisfying," the subject "I" is added, making it clear that it is the person speaking who read the whole book and found the ending unsatisfying.