Choose the correct preposition to complete the sentence:

Every employee is expected to abide ______ the newly introduced corporate policies.

The correct option is by.

Explanation:
In English grammar, certain verbs strictly pair with specific prepositions to form fixed phrasal verbs with distinct meanings.

The verb abide correctly pairs with the preposition by to form the phrasal verb "abide by". This phrase means to comply with, obey, accept, or follow a set of rules, agreements, or policies.

Let me break down why the other options are incorrect:
• on: "Abide on" is grammatically incorrect when referring to rules or policies.
• to: While the synonym "adhere" takes "to" (adhere to), "abide" specifically requires "by".
• with: Although "comply" takes "with" (comply with), "abide with" is an archaic phrase meaning to remain or dwell with someone, which does not fit the context of corporate policies.

Thus, inserting by completes the sentence correctly:
"Every employee is expected to abide by the newly introduced corporate policies."