Correct Answer - D
Let `AC=4x` and `BD=3x`
`:. OA=2x` and `OB=(3x)/2`
In right `Delta OAB`
`sqrt((2x)^(2)+((3x)/2)^(2))=40`
`4x^(2)+(9x^(2))/4=40^(2)=1600`
`16x^(2)+9x^(2)=1600xx4`
`25x^(2)=6400`
`x^(2)=6400/25`
`x=sqrt(6400/25)=80/5=16`
`:. AC =4x=4xx16=64`
`BD=3x=3xx16=48`
area `=1/2xxACxxBD`
`=1/2xx64xx48`
`=1536cm^(2)`