Injective and quasi injective modules

Question

Definition: An $R$-module $M$ is called quasi-injective module if for every submodule $N$, any $R$-homomorphism $N\to M$ extends to an endomorphism of $M$.

How can I prove that every injective module is quasi-injective ?

Answer 1

Hint: Use the definition of the injectivity in the case of $\iota:N\to M$ being the inclusion.