Textbook Problem

Let sets R, S, and T be defined as follows:

$\begin{array}{l}R=\left\{x\in Z|x\text{is}\text{divisible by 2}\right\}\\ S=\left\{y\in Z|y\text{is}\text{divisible by 3}\right\}\\ T=\left\{z\in Z|z\text{is}\text{divisible by 3}\right\}\end{array}$

Prove or disprove each of the following statements.

a. $R\subseteq T$

b. $T\subseteq R$

c. $T\subseteq S$