Joanna was eager to know her score on the science final exam. Ms. Filer would release the scores once she graded all the exams. Ms. Filer had at least 15 exams left to grade. Which number line represents the number of exams Ms. Filer had left to grade?
number line with a closed circle on number 15 and line shaded
left number line with an open circle on number 15 and line shaded
left number line with an open circle on number 15 and line shaded
right number line with a closed circle on number 15 and line shaded right