Answer:
A.The spring constant for B is one quarter of the spring constant for A.
Explanation:
If spring A oscillates at twice the frequency of spring B, and period is frequency inverted. It means spring B has a period twice of spring A's.
[tex]T_B = 2T_A[/tex]
As [tex] T = 2\pi\sqrt{\frac{m}{k}}[/tex], and the 2 springs have the same mass
[tex]2\pi\sqrt{\frac{m}{k_B}} = 2\pi\sqrt{\frac{m}{k_A}}[/tex]
[tex]\sqrt{k_A} = 2\sqrt{B}[/tex]
[tex]k_A = 4k_B[/tex]
[tex]k_B = k_A/4[/tex]
So A.The spring constant for B is one quarter of the spring constant for A. is the correct answer.