Can someone tell me/ me figure out what part of speech the underlined word is for 4, 5, 7, 9 and 10

What is one unique way in which the medium of tv can affect a message? a. by allowing the audience to review information and reflect on it b. by limiting the amount of coverage any one topic gets c. by using images and sound to give information context d. by reporting some types of information but ignoring other types