It's not a complete graph because property of a complete graph is

*K*_{n} has *n*(*n* − 1)/2 edges (a triangular number), and is a regular graph of degree *n* − 1.

here n=1 so 1*(1-1)/2 is not defined so it is not a complete graph

It's not clique because the definition of clique is

A **clique**, *C*, in an undirected graph *G* = (*V*, *E*) is a subset of the vertices, *C* ⊆ *V*, such that every two distinct vertices are adjacent. This is equivalent to the condition that the induced subgraph of *G* induced by *C* is a complete graph. In some cases, the term clique may also refer to the subgraph directly.

there is no subgraph in given graph which is complete

It's not connected graph because according to definition a graph should have atleast two vertices to show it is connected or not

Defination: A graph is **connected** when there is a path between every pair of vertices

in the question it is only mentioned that there is one vertex