Speed of sound at constant temperature depends on

Regarding the speed of sound in a gas, match the following:

$A$. Temperature of gas is made $4$ times and pressure $2$ times	$P$. Speed becomes $2\sqrt{2}$ times
$B$. Only pressure is made $4$ times without change in temperature	$Q$. Speed becomes $2$ times
$C$. Only temperature is changed to $4$ times	$R$. Speed remains unchanged
$D$. Molecular mass of the gas is made $4$ times	$S$. Speed becomes half

Estimate the speed of sound (in $m/s$) in air at standard temperature and pressure $(STP)$. The mass of $1$ mole of air is $29.0 \times 10^{-3} \; kg$.

Velocity of sound is maximum in

Find the frequency of the minimum distance between a compression and a rarefaction of a wire. If the length of the wire is $1\, m$ and the velocity of sound in air is $360\, m/s$,find the frequency in $sec^{-1}$.

What is the distance between consecutive condensation and rarefaction in longitudinal waves?