1. Give context-free grammars generating each of the following languages over $\Sigma=\{0,1\}$ : a) $\left\{0^{n} 1^{m} 0^{n}: m, n \geq 1 ight\}$ b) $\left\{0^{n} 1^{n} 0^{m} 1^{m}: m, n \geq 0 ight\}$ c) $\left\{0^{n} 1^{m} 0^{m} 1^{n}: m, n \geq 0 ight\}$ CS. JG. 009