Step 1: Understand the meaning of the underlined word.
The word prudent means careful, wise, and showing good judgment while making decisions.
Step 2: Interpret the sentence.
The sentence states that the company's expansion decision was considered prudent. This means the decision was thoughtful, sensible, and carefully planned.
Step 3: Analyse the options.
• (A) wise -- Incorrect. Wise is a synonym of prudent.
• (B) reckless -- Correct. Reckless means acting carelessly without considering the consequences, which is the opposite of prudent.
• (C) timely -- Incorrect. Timely refers to something happening at the right time and is not an opposite of prudent.
• (D) profitable -- Incorrect. Profitable means producing financial gain and is unrelated to prudence.
Step 4: Final conclusion.
\[
\boxed{\text{Prudent} \longleftrightarrow \text{Reckless}}
\]
Hence, the correct option is \(\boxed{(B)}\).