Select the grammatically correct form of the given sentence from the following options.
1
Police decline to name the weapon used in the incident but said the boy had used a handgun.
2
Police declined to name the weapon used in the incident but said the boy had used a handgun.
3
Police declined to name the weapon used in the incident but said the boy have used a handgun.
4
Police declined to name the weapon use in the incident but said the boy had used a handgun.