The correct option is C Less than 3000
To get the idea of multiplication we can simplify the number a bit so to guess 499 x 6 we can use 500 in place of 499, since 500 x 6 is easier to calculate.
500 x 6 = (5 x 6) x 100
= 30 x 100
= 3000
Since 499 is less than 500 so 499 x 6 will also be less than 500 x 6.
So 499 x 6 will be less than 3000.