The correct option is B X={6,9,12,15, . . .}
The set X represents all multiples of 3 greater than 3.
We know the multiples of 3 greater than 3 are 6,9,12,15,...
Since, the elements can go upto infinity, we will use ellipsis or three dots to signify elements going upto infinity.
Hence, In roster form X can be represented as:
X={6,9,12,15,...}