Two algorithms A$1,$ A$2$ solve a problem with running times of f$1($n$)$ and f$2($n$),$ respectively.

Then f$1($n$)$ in O$($f$2($n$))$ means which of the following statements is true

$2\mathrm{.}5$

$[$ A $]$ For all n$,$ f$1($n$)<=$ f$2($n$)$

$[$ B $]$ There exist n$0,$ such that for all n $>$ n$0,$ f$1($n$)<=$ f$2($n$)$

$[$ C $]$ There exist n$0$ and a constant c$,$ such that for all n $>$ n$0,$ f$1($n$)<=$ cf$2($n$)$

$[$ D $]$ A$1$ is running fast in all cases.

$[$ E $]$ None of the above.