Answer:
C, 1 and 2.
Explanation:
The square root of 81 repeating is 9.05, (Rounded)
-It goes on forever.
Since it goes on forever, it's not a whole number or a natural number, both kind of numbers never keep going on forever.
Which leaves us with Irrational and Real Numbers
Therefore, 1 and 2 is your answer.
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Happy New Year!