Step 1: Understanding the Question:
The question requires us to identify the correct meaning of the common English idiom ``spill the beans''.
We must select the option that best describes this figurative expression.
Step 2: Key Concepts and Idiomatic Meanings:
An idiom is a group of words established by usage as having a meaning not deducible from those of the individual words.
The phrase ``spill the beans'' is believed to have historical origins where voting was done using colored beans, and spilling them would reveal the results prematurely.
Step 3: Detailed Explanation:
• Option (C) - to reveal a secret: This is the correct definition of the idiom.
When someone ``spills the beans'', they disclose secret information, often prematurely or unintentionally, to others.
In the sentence, the person let out the secret information regarding his new car.
• Options (A) and (B): These are literal interpretations of the words ``cook'' and ``cut'' beans, which are incorrect because idioms are figurative.
• Option (D) - to speak truth: While revealing a secret involves sharing truth, ``spill the beans'' specifically refers to the act of exposing confidential or hidden information, rather than simply being honest.
Step 4: Final Answer:
Therefore, Option (C) is the correct answer.