Which of the following technique(s) can be used to study conformational changes in myoglobin?

Q. Which of the following technique(s) can be used to  study conformational changes in myoglobin?

P. Mass spectrometry

Q. Fluorescence spectroscopy

R. Circular dichroism spectroscopy

S. Light microscopy

(A) P only          

(B) P and S only             

(C) Q and R only        

(D) S only

Ans: Q and R only