For Fanning friction factor $f$ (for flow in pipes) and drag coefficient $C_{D}$ (for flow over immersed bodies), which of the following statements are true?

$P.$ $f$ accounts only for the skin friction

$Q.$ $C_{D}$ accounts only for the form friction

$R.$ $C_{D}$ accounts for both skin friction and form friction

$S.$ Both $f$ and $C_{D}$ depend on the Reynolds number

$T.$ For laminar flow through a pipe,$f$ doubles on doubling the volumetric flow rate.

1. $R, \:S,\: T$
2. $P, \:Q, \:S$
3. $P,\:R,\:S$
4. $P, \:Q,\: S,\: T$