Write an equation for the word problem: Katie had a ribbon that was 23 ½ inches long. After Katie cut the ribbon in two pieces, she had 8 ¼ inches of the ribbon left. How much ribbon did Katie cut from her original ribbon?
A23 ½ - r = 8 ¼
B23½ + 8¼ = r
C23½ + r = 8¼
D8¼ - r = 23½
A23 ½ - r = 8 ¼
B23½ + 8¼ = r
C23½ + r = 8¼
D8¼ - r = 23½