$A$ naturally occurring substance has the constitution shown below. How many stereoisomers may have this constitution?

Which of the following compounds is optically inactive?

Which one of the following is most reactive towards electrophilic reagent?

What is the possible number of stereoisomers for the compound $CH_3-CH=CH-CH(OH)-CH_3$?

Consider the hydrogen atoms attached to three different carbon atoms (labeled $1$,$2$ & $3$). Rank the attached hydrogen atoms in order from most acidic to least acidic.

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.