Stability order among these tautomer is :
`CH_(2)=overset(OH)overset(|)underset((I))C-CH_(2)-CH_(3)hArrCH_(3)-overset(O)overset(||)underset((II))(C)-CH_(2)-CH_(3)hArrCH_(3)-overset(OH)overset(|)(C)=underset((III))(CH)-CH_(3)`

CH_(3)-underset(CH_(3))underset(|)(CH)-CH=CH-CH_(2)-overset(O)overset(||)(C)-OH

CH_(3)CHOHCH_(2)-overset(CH_(3))overset(|)underset(CH_(3))underset(|)(C)-OH

Among the following four structures I to IV C_(2)H_(5)-overset(CH_(3))overset(|)underset((I))(CH)-C_(3)H_(7) CH_(3)overset(O)overset(||)(C)overset(CH_(3))overset(|)underset((II))(CHC_(2))H_(5) H-overset(H)overset(|**)underset(III)underset(H)underset(|)C C_(2)H_(5)-overset(CH_(3))overset(|)underset((IV))(CH)-C_(2)H_(5) it is ture thate

Arrange the following in order of their reactivity toward decarboxylation reaction :- underset(I)(CH-=C overset(O)overset(||)C-OH) " "underset(II)(CH_(2)=CH-overset(O)overset(|)C-OH)" " underset(III)(CH_(3)-CH_(2)-overset(O)overset(||)C-OH) " " underset(IV)(CH_(3)-overset(CH_(3))overset(|)CH-overset(O)overset(||)C-OH)

The IUPAC name of CH_(3)-overset(OH)overset(|)underset(H)underset(|)(C)-CH_(2)-overset(O)overset(||)(C)-CH_(3) is: