How long?

The sum of the medians of triangle is $S$ , and the perimeter of the same triangle is $P$ .

Which of the following statements is true for sure?

$\quad$ A : $S\leq\dfrac{3}{4}P$

$\quad$ B : $\dfrac{3}{4}P\leq S\leq P$

$\quad$ C : $P\leq S\leq\dfrac{5}{4}P$

$\quad$ D : $\dfrac{5}{4}P\leq S$