Match the following:

Elements	Flame Color
$1$. $Li$	$a$. Yellow
$2$. $Na$	$b$. Red-violet
$3$. $Rb$	$c$. Blue
$4$. $Cs$	$d$. Crimson red

(B) The flame colors of alkali metals are as follows:
$1$. $Li$ (Lithium) imparts a crimson red color to the flame.
$2$. $Na$ (Sodium) imparts a yellow color to the flame.
$3$. $Rb$ (Rubidium) imparts a red-violet color to the flame.
$4$. $Cs$ (Caesium) imparts a blue color to the flame.
Therefore,the correct matching is: $1-d, 2-a, 3-b, 4-c$.
The correct option is $(B)$.