The answer would be "Estoy escribiendo" because estan means they are, esta means he is, and estamos means we are, adn we are talking about something in first person and estoy means I am so this perfectly fits it
Hope this helps
The correct answer is A. Hay un profesor con el estudiante.
The sentence says - There is A professor with THE student. In Spanish, the article A is either UN or UNA (depending on the gender) for singular, and UNOS and UNAS for plural. The article THE is either EL or LA, depending on the gender.
