Which of the following metal is most ductile? 

Gold 

The correct answer is option 4. Gold.

Ductility is a property of a material that describes its ability to deform under tensile stress (pulling force) by elongating or stretching without breaking. A highly ductile material can be drawn into thin wires or elongated into thin sheets without fracturing.

Gold is renowned for its exceptional ductility among metals. It is considered one of the most ductile elements, if not the most ductile. This characteristic is due to its atomic structure and bonding. Gold atoms have relatively weak metallic bonds, allowing them to slide past each other easily when subjected to tensile stress.

When gold is drawn into wires, its atoms can rearrange themselves without significant resistance, enabling the metal to be elongated to a remarkable extent. This property makes gold highly suitable for various applications requiring fine wires, such as in electronics, telecommunications, and jewelry making.

In comparison to the other metals listed:

Copper and silver are also highly ductile metals, but gold typically exhibits even greater ductility.

Aluminum is ductile but less so than gold, copper, and silver.

Overall, gold stands out as one of the most ductile metals, making it valuable for a wide range of practical and decorative applications.