Which kind of 4-bar mechanism is O2ABO4?

1. Double crank mechanism
2. Crank-rocker mechanism
3. Double rocker mechanism
4. Parallelogram mechanism

AB = √(240)² + (160 − 60)²
= 260 mm
= = l_AO₂ + l_O₂_O₄ < l_AB + l_BO₄
= and O₂_{O₄ is fixed link. It will act as a crank-rocker mechanism}