Answer: d. Well, I have never ever figured out why using plastic grocery bags was so bad!
Step-by-step explanation:
Informal style often includes slang, broken syntax, figures of speech, and informal language in general. Similarly, casual style is often written in the first person, and does not require the author to follow any particular writing form. It is easy to see that the sentence that is written in an informal and casual style is sentence D: Well, I have never ever figured out why using plastic grocery bags was so bad! This is seen by the use of words such as 'well', and phrases such as 'never ever.' These words, in combination with the topic discussed, indicate that the style is informal.