Answer:
The suitable options would be: a. & b.
Explanation:
Captions are titles also known as headlines, headings, subtitles or legends, depending on how are they used or displayed; they usually provide a brief explanation or meaning of an image, illustration, article, poster, cinematography or video-clip.
They are also used to communicate what is being said with words on the screen when a movie or video is being played, generally at the bottom of a TV screen or movie screen, and to provide translation for other languages audiences as well.
Thereby the correct answer is clearly (C.)
