Total number of compounds with Chiral carbon atoms from following is __________ .

\(\text{CH}_3 - \text{CH}_2 - \text{CH}(\text{NO}_2) - \text{COOH}\)
\(\text{CH}_3 - \text{CH}_2 - \text{CHBr} - \text{CH}_2 - \text{CH}_3\)
\(\text{CH}_3 - \text{CH}(\text{I}) - \text{CH}_2 - \text{NO}_2\)
\(\text{CH}_3 - \text{CH}_2 - \text{CH}(\text{OH}) - \text{CH}_2\text{OH}\)
