To analyze the situation, we know the following:
- The school opened in 2018, starting with an enrollment (S) of 1,500 students. This means at time \( t = 0 \) (which corresponds to the year 2018), the number of students is 1,500.
- In 2022, which is 4 years after the school opened (i.e., \( t = 4 \)), there were 1,900 students enrolled.
To determine the y-intercept of this linear function of enrollment, we look for the point on the graph where \( t = 0 \). Since \( t = 0 \) corresponds to the year 2018 when the school started, the y-coordinate is the initial enrollment, which is 1,500.
Thus, the point that represents the y-intercept (the number of students enrolled when \( t = 0 \)) is:
\[ (0, 1,500) \]
Therefore, the correct choice for the y-intercept placement is:
(0, 1,500)