The hyperconjugative stabilities of tert-butyl cation and 2-butene, respectively, are due to

A

$$\sigma \rightarrow p$$ (empty) and $$\sigma \rightarrow \pi$$ electron delocalisations.

B

$$\sigma \rightarrow \sigma$$ and $$\sigma \rightarrow \pi$$ electron delocalisations.

C

$$\sigma \rightarrow p$$ (filled) and $$\sigma \rightarrow \pi$$ electron delocalisations.

D

p (filled) $$\rightarrow \sigma^*$$ and $$\sigma \rightarrow \pi^*$$ electron delocalisations.