When a 0.05-kg mass is attached to a vertical spring, it is observed that the spring stretches 0.03 m. The system is then placed horizontally on a frictionless surface and set into simple harmonic motion. What is the period of the oscillations? 
选项为:A:$$0.75s$$  B:$$0.12s$$  C:$$0.35s$$  D:$$1.3s$$  请回答其中一个选项.