Understanding Prefixes: Choosing the Right Fit

The question asks us to select the most suitable prefix to complete the sentence: "I felt _______ secure talking to a stranger and so-called the police." We need a prefix that changes the meaning of "secure" to fit the context of feeling unsafe or not confident, which would lead someone to call the police.

Let's look at the given options and how they typically combine with words or the word "secure":

• dis-: This prefix often means "lack of," "not," "opposite of," or "apart." Examples include disallow, disagree, disappear. While "discomfort" is a word, "dissecure" is not a standard English word.
• un-: This prefix typically means "not" or "opposite of." Examples include unhappy, unkind, undo. "Unsecured" is a word, often used for things like loans (not secured by assets) or doors (not physically secured). "Unsecure" can also mean not feeling secure, but "insecure" is more common when referring to a feeling of lack of safety or confidence.
• de-: This prefix often means "down," "away," "opposite action," or "remove." Examples include demote, deactivate, detach. "Desecure" is not a standard English word.
• in-: This prefix can mean "in," "into," "on," "towards," or more commonly, "not" or "without" when used with certain adjectives (like 'active', 'dependent'). When combined with "secure," it forms the word "insecure."

Analyzing the Word "Insecure"

The word "insecure" means:

• Not feeling confident or certain; apprehensive.
• (Of a thing) not firmly fixed; liable to give way.
• (Of a place) exposed to danger or threat.

In the context of the sentence "I felt _______ secure talking to a stranger and so-called the police," the feeling described is one of apprehension, lack of confidence in the safety of the situation, or feeling exposed to danger. This meaning aligns perfectly with the definition of feeling "insecure."

Using other prefixes like 'dis-' or 'de-' does not form a correct or standard English word with 'secure'. While 'unsecure' exists and can sometimes mean not feeling secure, 'insecure' is the most common and appropriate word to describe the *feeling* of vulnerability or lack of confidence when encountering a stranger in a concerning situation, which prompts calling the police.

Therefore, the most suitable prefix is in-, forming the word insecure.

The completed sentence reads: "I felt insecure talking to a stranger and so called the police."