You are analyzing a worker's task of assembling a pen. The task sequence includes the following steps:

Reach for the pen barrel.

Grasp the pen barrel.

Reach for the ink cartridge.

Insert the ink cartridge into the barrel.

Reach for the pen cap.

Attach the pen cap to the barrel.

Using Therblig analysis, identify at least FOUR $(4)$ Therbligs involved in this sequence and propose a solution to improve the task's efficiency by reducing unnecessary movements.