Cis-trans isomerism, also known as geometric isomerism, occurs when compounds have the same molecular formula and connectivity but differ in the spatial arrangement of their atoms. This type of isomerism is commonly observed in compounds with a double bond or a ring structure.

In the given options, only compound A, 2-butene, contains a double bond. Therefore, it is the only compound that can exhibit cis-trans isomerism. Let's understand why:

- 2-butene: 2-butene is an alkene with the molecular formula C4H8. It contains a double bond between two carbon atoms. The double bond restricts the rotation around the bond, leading to two possible arrangements of the substituents on the carbon atoms.
- Cis-2-butene: In cis-2-butene, the two methyl groups are on the same side of the double bond. This arrangement creates a cis isomer.
- Trans-2-butene: In trans-2-butene, the two methyl groups are on opposite sides of the double bond. This arrangement creates a trans isomer.

The cis and trans isomers of 2-butene have different physical and chemical properties. For example, their melting points, boiling points, and reactivity may vary. This is because the spatial arrangement of atoms affects molecular interactions and the ability to undergo certain reactions.

On the other hand, the other compounds mentioned in the options do not have a double bond or a ring structure. Therefore, they cannot exhibit cis-trans isomerism. They may have other types of isomerism like structural isomerism or conformational isomerism, but not cis-trans isomerism.

In conclusion, out of the given options, only compound A, 2-butene, can exhibit cis-trans isomerism due to its double bond.

At double bonded carbon, there is two different group