The correct option is D 42
To get the multiples of number 7, all we have to do is multiply 7 by 1, 2, 3 and so on.
That is,
7×1=7,
7×2=14,
7×3=21,
7×4=28,
and so on are the multiples of 7.
Hence, the first three multiples of 7 are 7, 14 and 21.
∴ The sum of the first three multiples of 7 is given by 7+14+21=42.