Convert the sentence provided below from its passive voice structure to an active voice structure:
It was being reported by several sources that the mission had been compromised internally.

The correct option is: Several sources were reporting that the mission had been compromised internally.

Step-by-Step Explanation:

1. Analyze the Original Sentence:
The given passive sentence is: "It was being reported by several sources that the mission had been compromised internally."
Main passive verb clause: "was being reported" (Past Continuous Passive Voice).
Agent performing the action: "several sources" (introduced by "by").

2. Identify the Active Voice Rules for Past Continuous Tense:
• Passive Structure: Subject + was/were + being + V3 (past participle) + by + Agent
• Active Structure: Agent (becomes Subject) + was/were + V-ing (present participle) + Object

3. Convert to Active Voice:
• The agent "several sources" becomes the active subject.
• The verb phrase "was being reported" converts to the past continuous active verb "were reporting" (since "sources" is plural).
• The subordinate clause describing what was reported remains intact: "that the mission had been compromised internally."

Combining these parts gives the active voice sentence:
"Several sources were reporting that the mission had been compromised internally."