Which of the Following Simultaneous Joint Actions Illustrate Countercurrent Biarticular

Which of the following simultaneous joint actions illustrate countercurrent biarticular muscle action?
1) flexion at knee--extension at hips
2) extension at knee--flexion at hips
3) flexion of fingers--flexion at wrist
4) extension of fingers--flexion at wrist

A) flexion at knee--extension at hips, extension at knee--flexion at hips
B) extension at knee--flexion at hips, flexion of fingers--flexion at wrist
C) flexion at knee--extension at hips, extension at knee--flexion at hips, flexion of fingers--flexion at wrist
D) extension at knee--flexion at hips, flexion of fingers--flexion at wrist, extension of fingers--flexion at wrist