How many isomers (cyclic and acyclic) are possible for a compound with molecular formula $C_3H_6O$?

Which one of the following molecules does not show stereoisomerism?

Find out the statements which are not true.
$A$. Resonating structure with more number of covalent bonds and lesser charge separation are more stable.
$B$. In electromeric effect,an unsaturated system shows $+E$ effect with nucleophile and $-E$ effect with electrophile.
$C$. Inductive effect is responsible for high melting point,boiling point and dipole moment of polar compounds.
$D$. The greater the number of alkyl groups attached to the doubly bonded carbon atoms,higher is the heat of hydrogenation.
$E$. Stability of carbanion increases with the increase in $s$-character of the carbon carrying the negative charge.
Choose the correct answer from the options given below.

Consider the sets $I$,$II$,and $III$. Identify the set$(s)$ which is (are) correctly matched.
$I$. $\text{Staggered ethane} > \text{eclipsed ethane} \dots \dots \dots \text{torsional strain}$.
$II$. $2, 2-\text{Dimethylbutane} > 2-\text{methylpentane} \dots \dots \dots \text{boiling point}$.
$III$. $cis-\text{but}-2-\text{ene} > trans-\text{but}-2-\text{ene} \dots \dots \dots \text{dipole moment}$.

Among the following,the most stable isomer is

How many stereoisomers are possible for the following molecule?