OPTIONS:
[1]. movement of tectonic plates;
[2]. dry streambeds;
[3]. long periods of time;
[4]. Physical weathering;
[5]. Time and energy;
[6]. short periods of time;
[7]. massive damage;
[8]. calving glaciers;
Given those answer options, answer the question: You are presented with the quiz "Flowing water forms most canyons through erosion over what?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "most canyons are formed by flowing rivers through erosion over long periods of time" and "rivers and glaciers are made of water". So, what's the best answer to the question?
A:
[3].