Explanation:

Introduction:
Catenation is the ability of an atom to form bonds with other atoms of the same element to form long chains or rings. It is a unique property of carbon that allows it to form diverse and complex structures, such as hydrocarbons and biomolecules. This property is attributed to the small size and the ability of carbon atoms to form strong covalent bonds.

Analysis:
In the given options, carbon (C), silicon (Si), germanium (Ge), and lead (Pb) are p-block elements. Carbon is well-known for its catenation ability, where it can form long chains and rings with other carbon atoms. Silicon and germanium, being in the same group as carbon, also exhibit catenation to a certain extent. However, lead, being a heavier element, does not show significant catenation properties.

Explanation:
Carbon (C):
Carbon is known as the "element of life" due to its unique ability to form diverse compounds by catenation. Carbon atoms can form strong covalent bonds with other carbon atoms, allowing for the formation of long chains, branched structures, and rings. This property is the basis for the vast diversity of organic compounds found in living organisms.

Silicon (Si) and Germanium (Ge):
Silicon and germanium, being in the same group as carbon, also have some catenation ability. However, their catenation properties are much weaker compared to carbon. Silicon and germanium can form chains and rings with other atoms of the same element, but these structures are generally not as stable or diverse as those formed by carbon.

Lead (Pb):
Lead, being a heavier element, does not exhibit significant catenation properties like carbon, silicon, or germanium. The larger size and higher atomic weight of lead make it difficult for the lead atoms to form strong covalent bonds with each other, limiting their ability to form long chains or rings.

Conclusion:
Among the given p-block elements, lead (Pb) is the element that does not show catenation. Carbon (C), silicon (Si), and germanium (Ge) exhibit catenation to varying degrees, with carbon being the most prominent example of this property.