Two Springs Are Connected in Series to a 1

Multiple Choice

Two springs are connected in series to a 1.0-kg mass. If the spring constants are k₁ = 15.0 N/m and k₂ = 10.0 N/m, the period of the motion is

A) 1.26 s.
B) 2.56 s.
C) 2.81 s.
D) 3.61 s.