Select the most appropriate option to fill in the blank and make a grammatically correct sentence.

The driver of the car probably holds the key to ______ the crime.

solving

The most appropriate option to fill in the blank and make a grammatically correct sentence is:

☀ solving

The sentence would read: "The driver of the car probably holds the key to solving the crime."

Explanation: "Solving" is the gerund form of the verb "solve," and it is used here to indicate the action of finding a solution to the crime. The other options don't fit the context:

• Solves: This is the present tense form of the verb and doesn't match the structure of the sentence.

• Solved: This is the past tense form of the verb and doesn't match the structure of the sentence.

• Solution: This is a noun and doesn't fit the context of an action related to solving the crime.