The given number is 799. We need to find the 10's digit of this number.

To find the 10's digit, we need to divide the number by 10 and take the remainder. The remainder will give us the digit in the 10's place.

Let's perform the division:

799 ÷ 10 = 79 remainder 9

The remainder is 9, which means that the digit in the 10's place is 9.

However, none of the answer options given match the digit 9.

So, let's try again.

To find the 10's digit, we can also divide the number by 10 and take the quotient. The quotient will give us the digit in the 10's place.

Let's perform the division:

799 ÷ 10 = 79.9

The quotient is 79.9. Since we are looking for a digit, we can ignore the decimal part and focus on the whole number part, which is 79.

The digit in the 10's place is the last digit of this whole number part, which is 9.

Therefore, the correct answer is 9, not one of the options provided.

Conclusion: The given options do not include the correct answer. The correct 10's digit of 799 is 9.

If we see the increasing powers of 7, we observe that there is a general trend that is being followed by the digits in Tens' Place.