Answer :

I believe it is "such as" because that fits an example best, don't you think?

Answer:

Such as is the correct answer.

Explanation:

Linking phrases are used to connect two or more ideas; another use for them is to link two clauses in a sentence and they can connect, add or contrast ideas or show an example or reason.

Such as is one of these phrases used to introduce or provide specific examples of something; an illustration can also be considered an example, so the correct answer is letter D.