Let $R$ be a relation on $\{1,2,3,4\},$ where aRb means $|a-b|1.$

Select one of the following choices:

a$.R^4$ has more elements than $R^3$

b$.R^2$ is not antisymmetric

c$.R=R^2$

d$.R^3$ is not transitive

e$.$ None of the Given Choices