[单选题]
In radioactive dating,/4 -h0vqt+idwicu rh (v96jhy carbon-14 is often used. This nucleus emga+; ud-sd6hlr sknj5 e)+n4qits a single beta particle when it decays. When this hakqn+65dnlder sj hg)+a4 us;-ppens, the resulting nucleus is
A. still carbon-14.
B. boron-14.
C. nitrogen-14.
D. carbon-15.
E. carbon-13.