Identify the sentence with correct parallel structure. Public speaking, writing e-mails, and designing presentation visuals are difficult for many people. To speak publicly, to write e-mails, and designing presentation visuals is difficult for many people.

The correct parallel structure is

Public speaking, writing e-mails, and designing presentation visuals are difficult for many people.

Explanation:

Parallel Structure in English Grammar:

Parallel structure in English grammar is known as parallelism. It is a technique of writing or speaking in which sentences have identical grammatical structure like

Subject + verb structure can been seen in the following example

They play, they write and they walk daily.

So in our case this sentence " Public speaking, writing e-mails, and designing presentation visuals are difficult for many people." has same grammatical structure as each clause is starting with verb+ing like speaking, writing and designing.