What is the time complexity of finding the diameter of a graph $G=(\cal V,E)$?

• $\cal{O}(|V|^2)$
• $\cal{O}(|V|^2+|V| \cdot |E|)$
• $\cal{O}(|V|^2\cdot |E|)$
• $\cal{O}(|V|\cdot |E|^2)$

^{The diameter of a graph $G$ is the longest distance between two vertices in graph.}

I have no idea what to do about it, I need a complete analysis on how to solve a problem like this.