Concept:Rationalize the denominator by multiplying numerator and denominator by the conjugate of the denominator.Explanation:Start with 1−2​2​.Multiply numerator and denominator by the conjugate (1+2​):(1−2​)(1+2​)2×(1+2​)​.Denominator simplifies: (1)2−(2​)2=1−2=−1.Numerator: 2+22​.So −12+22​​=−(2+22​)=−2(1+2​).Answer:A. −2(1+2​)