Transcript text: Zhenghan notices a strong correlation between whether a person is a freshman, sophomore, junior, or senior in college and the number of credit hours that a student has registered for. As students' years in college increase, they tend to register for fewer credit hours. Based on this information, the correlation coefficient between years in college and number of credit hours is closest to:
$+0.70$
$-0.20$
$+0.20$
$-0.70$