The second and third option
To find exponent expressions, use this rule: base stays the same, subtract the exponents
3 to the power of 2
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3 to the power of 5 = 3 to the power of -3
There is no such thing as negative exponents, so you find the reciprocal of the expression by flipping you result
3 to the power of -3 flipped: 1/3 to the power of 3 (the third option) and the second option (when result is simplified)