To determine which number has the greatest absolute value, we need to evaluate the absolute value of each option:
A. |5| = 5
B. |-3| = 3
C. |-9| = 9
D. |1| = 1
Now, comparing the absolute values:
- For 5: absolute value is 5
- For -3: absolute value is 3
- For -9: absolute value is 9
- For 1: absolute value is 1
The greatest absolute value is 9, which corresponds to option C, -9.
So, the answer is C. -9.