Step-by-step explanation:
Viscosity is defined as the ability of a liquid substance to oppose its flow. So, more is the mass of a liquid more will be its viscosity.
Since, the given option of hydrocarbons show different compounds. And, longer is the chain of hydrocarbon more will be its mass.
As a result, more difficulty it will face to flow. Therefore, it means greater will be the viscosity of hydrocarbon that has longer chain of carbon and hydrogen atoms.
Thus, we can conclude that given hydrocarbons are ranked from most to least viscous as follows.
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