[单选题]
Doubling only the mass of a vibrating mass-and-sxv 1v(s 3vmsloa--lbi-ki2 d3prvuz 3)d4c5v xxing system produces what effect on the system's mechancv z)543xdvux ical energy?
A. increases the energy by a factor of two
B. increases the energy by a factor of three
C. increases the energy by a factor of four
D. produces no change