Molecularity of Reaction

Q. Karthik and Arun studying chemical kinetics together. They came around this equation: $N_2+3H_2\to 2N{H}_3$.
Karthik concluded that the molecularity of the reaction is 4 as one molecule of $N_2$ is reacting with three molecules of $H_2$.
But Arun said that molecularity of 4 is very unlikely as the probability of 4 molecules colliding simultaneously is almost zero.
As they both contradicting one another can you tell who is correct and who is wrong.

1. Karthik is correct, Arun is wrong
2. Both are wrong
3. Karthik is wrong Arun is correct
4. Both are correct