Correct Option: A

Let M and W be the earnings of men and women respectively .
According to question ,
4 ( 5M + 6W ) = 2160
⇒ 20M + 24W = 2160 .................( 1 )
5 ( 8M + 10W ) = 4400
⇒ 20M + 25W = 2200.................( 2 )
On solving above equations , we get
M = 60 and W = 40
Now 4 men and 9 women earn ₹ 1800 in say, D days.
D ( 4M + 9W ) = 1800 ..............( 3 )
Putting the values of M and W in above equation ( 3 ) , we get
D ( 4 x 60 + 9 x 40 ) = 1800 ⇒ D ( 240 + 360 ) = 1800 ⇒ 600D = 1800