In the prooton decoupled ${ }^{13} \mathrm{C}$ and ${ }^{31} \mathrm{P}$ NMR spectra of $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{P}=0$, the number of lines observed, respectively, are
(a)two and one
(b)one and two
(c)three and one
(d)two and two.
Answer
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