The girl had a jovially outlook on her life.
The noun in this sentence which is uncountable, meaning that it names something that cannot be counted is the noun water.
You cannot count how many waters there are - it is uncountable. The other nouns, students and pitcher are countable, so they cannot be the correct answers, but rather water is.
What people communicate is information about subjects and events, people and processes.This section draws on Bruce Bimber, Information and American Democracy: Technology in the Evolution of Political Power (New York: Cambridge University Press, 2003), especially 9–12. It can be true or false, fiction or nonfiction, believable or not. We define it broadly to encompass entertainment, news, opinion, and commentary.