The following pairs of words bear a certain common relationship, except one pair. Choose the odd pair of words.

Analyzing the relationship in each pair:

Option 1: Beautician : Parlour

A beautician works at a parlour. This shows a person-to-workplace relationship.

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Option 2: Chemist : Medicine

A chemist deals with or dispenses medicine. This shows a person-to-product relationship, not a person-to-workplace relationship.

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Option 3: Lawyer : Court

A lawyer works at a court. This shows a person-to-workplace relationship.

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Option 4: Engineer : Site

An engineer works at a site. This shows a person-to-workplace relationship.

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Options 1, 3, and 4 all follow the pattern: Professional : Workplace

Option 2 follows the pattern: Professional : Product/Material

Therefore, Option 2 (Chemist : Medicine) is the odd pair as it does not represent a person-to-workplace relationship like the other three pairs.