More than one correct
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Singlet carbene is electron deficient species with one lone pair and two sigma bonds.
Total electrons around the carbon of the carbene is 6 so that is the reason any electron donating group can increase the stability of the carbene.Now OH benzene ring are electron donating groups and nitro groups are electron withdrawing group so in a question the stability of the carbene of the third formula is more than that of the first and first has more stability than that of the second.
HCC6H4(4-OH) > HCPh > HCC6H4(4-NO2) OR iii >i > ii .
So except for option C, all other three options are correct. I-e A: HCC6H4(4-NO2) < HCPh , B: HCC6H4(4-NO2) < HCC6H4(4-OH), D: HCPh < HCC6H4(4-OH). Stability of HCC6H4(4-OH) is more than HCC6H4(4-NO2) so option C is not correct.