In trying to escape, the thief ran … the police.

Analyze the question: The sentence is "In trying to escape, the thief ran __ the police." We need the preposition that fits the meaning and idiom.

Explain the concept: In English, the phrasal verb "run into" has two common meanings:

1. To collide with something or someone.
2. To meet someone unexpectedly.

Both meanings fit the situation. A thief trying to escape and accidentally meeting or bumping into the police is a classic use of "ran into".

Check each option:

• A. upon: "Ran upon" is archaic and rarely used. "Run upon" is not idiomatic here.
• B. by: "Ran by the police" means he passed them. This doesn't suggest an unexpected encounter, and it makes little sense as a result of trying to escape.
• C. into: "Ran into the police" means he unexpectedly met or collided with them. This is natural and idiomatic, and it fits the irony of trying to escape and meeting the police.
• D. through: "Ran through the police" would mean he passed through the police, as if they were a crowd or a barrier. This is unnatural.

Answer: The correct option is **C.

Tip: In "ran ___ someone" questions, think of "run into" as "meet by chance." Also remember related phrasal verbs: run into (meet unexpectedly), run out of (exhaust supply), run over (knock down with a vehicle), and run away from (flee).