A compound possessing optical isomerism provided it has the molecular formula C₇H₁₆, would be:

The compound that has least hindered rotation around carbon-carbon bond is-

Arrange the following carbanions in order of their decreasing stability:

A. \(\mathrm{H}_3 \mathrm{C}-\mathrm{C} \equiv \mathrm{C}^{-}\)
B. \(\mathrm{H}-\mathrm{C} \equiv \mathrm{C}^{-}\)
C. \(\mathrm{H}_3 \mathrm{C}-\mathrm{\bar{C}H_2}\)

1. A>B>C

2. B>A>C

3. C>B>A

4. C>A>B