The rules for solubility are simple, Like dissolves like. With water as the solvent, we want the solute to have intermolecular forces similar to water: Polar with H-bonding & dipole-dipole interactions.
Let's see:
Br-Br - non-polar, only London Dispersion Forces, so number 2 is not correct.
S=C=S (CS2) - non-polar, like CO2, only London Dispersion Forces, it is not correct.
Carbon tetrachloride (CCl4) - non-polar tetrahedral shape, only LDF, It is not correct.
CH3-CH2-OH - polar, with H-bonding & dipole-dipole forces, so it is correct.
Answer: ethanol (CH3CH2OH)
