Directions: Select the option that correctly converts the given sentence into indirect speech.

The detective stated, "We have been monitoring the suspect for weeks, but the evidence we have been collecting is becoming conclusive, and we will make an arrest soon."

The correct option is: "The detective stated that they had been monitoring the suspect for weeks, but the evidence they had been collecting was becoming conclusive, and they would make an arrest soon."

To convert the given sentence from direct speech into indirect speech, we must apply standard rules for pronoun and tense backshifting:

1. Conjunction and Reporting Verb: The reporting clause "The detective stated" is retained, and the quotation marks are removed, adding the conjunction "that".
2. Pronoun Change: The first-person plural pronoun "We" (and "we") changes to the third-person plural pronoun "they".
3. Tense Changes:
- Present Perfect Continuous "have been monitoring" changes to Past Perfect Continuous "had been monitoring".
- Present Perfect Continuous "have been collecting" changes to Past Perfect Continuous "had been collecting".
- Present Continuous "is becoming" changes to Past Continuous "was becoming".
- Future modal verb "will make" changes to "would make".

Putting it all together, the indirect speech becomes:
"The detective stated that they had been monitoring the suspect for weeks, but the evidence they had been collecting was becoming conclusive, and they would make an arrest soon."