Explanation : 1. We can use “Depth First Search” Algorithm,
to check it there is a cycle is an undirected
graph. I t we encounter any “back edge” in
“Depth first search” then given undirected
graph has a cycle. Also, If there is a cycle in
the Undirected graph, we must encounter a
“back edge” in DFS. And, DFS can be done in
O(| E| + | V| ) time for graph G = (V, E). So, it
can is in F.
2. P ≤ NP, So, it is also in NP.
3. NP - complete problem A ∈ NP. By, Definition
Every problem in NP can be solved in
polynomial time using non-deterministic
turing machine.
So, Answer is (A) i.e. 1, 2, and 3 are true.