The sentence below contains two errors in grammar usage. Read the sentence and the question that follows. Kelsey knew that, after working for days in the hot sun, her garden looked better then it had last year. Which version of the sentence has been correctly edited for grammar usage? A. Due to working for days in the hot sun, Kelsey's garden looked better than it had last year. B. Kelsey knew that, after working for days in the hot sun, her garden looked better than it had last year. C. After Kelsey had worked for days in the hot sun, she knew her garden looked better than it had last year. D. Kelsey knew her garden looked better than it had last year, after she had worked on it for days in the hot sun.

C. After Kelsey had worked for days in the hot sun, she knew her garden looked better than it had last year.

and you know this how?

The original sentence contains two errors in grammar usage. The first error is the use of "then" instead of "than" when making a comparison. The second error is the incorrect placement of the phrase "after working for days in the hot sun." Option C corrects both errors by using "than" and placing the time phrase "after working for days in the hot sun" in the correct position in the sentence.