Which line in the following program is a comment line?

$1$: print$("$Your lucky number is$...")$

$2$: lucky $=7$

$3$: # Display the lucky number

$4$: print$($lucky$)$

Question $9$Answer

a$.$

Line number $2$

b$.$

Line number $1$

c$.$

Line number $3$

d$.$

Line number $4$