Stepping outside her school, Katrina walked 40 m towards South to reach an ice - cream parlor. From there, she took a left turn and walked 15 m to reach a bus stop. She then took a left - turn and walked for another 30 m to reach the central park. What is the approximate shortest distance between the ice - cream parlor and the central park?

• A. 37.5 m
• B. 33.5 m
• C. 46 m
• D. 50 m