Final answer:
The passive form of 'We have won a number of matches at the state level' is 'A number of matches at the state level were won by us.' This form uses the past participle 'won' with a form of 'to be' and includes the agent 'by us' and the context 'at the state level.'
Step-by-step explanation:
The passive form of the sentence 'We have won a number of matches at the state level' transforms the subject of the sentence from the doer of the action (active voice) to the receiver of the action (passive voice). To construct the passive voice, we commonly use a form of the verb 'to be' with the past participle of the main verb and include 'by' plus the original subject if necessary. Based on the given options, the correct passive form of the sentence would include details about the location where the matches were won. Therefore, the most complete and correct passive construction is:
Option 2: A number of matches at the state level were won by us.
This sentence now has the matches as the subject being acted upon and includes the 'by us' phrase to indicate who originally took the action. It also retains the detail of the 'state level', which is important for context.