Under ambient conditions, which among the following surfactants will form a micelle in aqueous solution at the lowest molar concentration?

Micelles may be defined as aggregates of long-chain diphilic surfactant molecules or ions formed spontaneously in their solutions at a definite concentration. Micelles are formed by the cooperative binding of monomers to one another at concentrations exceeding a rather narrow region called the critical micellization concentration (CMC). Greater is the size of the hydrophobic chain, the less will be its solubility in water, and its chances to form a micelle will be more. Thus, CH3(CH2)15N(CH3)3Br⁻ will form a micelle in aqueous solution as it has the longest hydrophobic chain.