In this problem, we are trying to translate a given situation into logical notation.
We are given
p: I work out every day.
q: I eat healthily
r: I will get sick.
We are trying to translate "If I work out every day and eat healthily, I will not get sick."
We are essentially saying that if we do p and q, then r will not happen. Let's take a look at each part.
The notation for "and" is

Therefore, we can group p and q together as

Since these must happen together before reaching the conclusion, we should also include the parentheses:

Next, we are saying that r will not happen. The notation for "not" is

But in your question, we need to use ~. So, we have the last part of the statement as

Since p and q imply ~r, we can write the entire statement as:

The correct answer is C.