2. Replace the words in bold with a noun clause. What I regret most about having chicken pox is mis A. the endless itching B. having to take medicine I C. that I missed the class trip D. No change needs to be made to this sentence.

## Step 1<br />The problem asks us to replace the words in bold with a noun clause. A noun clause is a dependent clause that functions as a noun in a sentence. It can be a subject, an object, or a complement.<br /><br />## Step 2<br />In the sentence "What I regret most about having chicken pox is mis", the words in bold are "mis". We need to replace "mis" with a noun clause.<br /><br />## Step 3<br />Looking at the options, we can see that option C, "that I missed the class trip", is a noun clause. It can function as a noun in a sentence, which is what we need.<br /><br />## Step 4<br />Therefore, the correct answer is option C.