3) C

We first need to take the difference between each of their birthdays and see which difference is divisible by 7.

182 – 128 = 54

218 – 128 = 90

281 – 128 = 153

218 – 182 = 36

281 – 182 = 99

281 – 218 = 63

The only difference which is divisible by 7 is 63. This equals to exactly 9 weeks. Adam is born on the 218th day whilst Tara is born on 281st day. This means that Tara was born exactly (exactly means on the same day of the week) 9 weeks after Adam on the same day.

Hence, Adam and Tara is the answer. Option C.