Select the most appropriate option to substitute the underlined segment in the given sentence.
The manager, decided at last to bring the stenographer to book for her illegal money transactions after trying to ignore it several times.

The correct answer is make her accountable for her conduct.

Explanation:
The idiom "bring someone to book" means to hold someone accountable for their actions, punish them, or require them to explain their wrongdoings.
In the context of the sentence, the manager finally decides to hold the stenographer accountable for her illegal money transactions after ignoring the issue multiple times.

Analysis of Options:
• bring her for a detailed investigation: Incorrect. This refers to carrying out an inquiry rather than directly holding someone accountable or punishing them.
• take her into great confidence: Incorrect. This means sharing private or secret information with someone in trust.
• place her in a safe supportive position: Incorrect. This means protecting or placing someone in a secure environment.
• make her accountable for her conduct: Correct. This precisely captures the definition of the idiom "bring to book".