[单选题]
Relative to a stationary observer, xh-j(: ;zl u/y b.zlkh;tdrx7a mo(d rux/pxlnl k228u2q ving clock
A. always runs slower than normal.
B. always runs faster than normal.
C. keeps its normal time.
D. can do any of the above. It depends on the relative velocity between the observer and the clock.
