What should be used to maintain proper alignment when repositioning an immobile client?

To maintain proper alignment when repositioning an immobile client, using pillows and bath blankets is essential. These items help to provide cushioning and support, allowing for comfortable positioning that can alleviate pressure points on the body. Pillows can be placed under various parts of the body, such as the head, back, and knees, to enhance support and ensure that the client's spine and limbs are properly aligned. Bath blankets can also be used to keep the client covered and warm, promoting a sense of security and comfort during repositioning.

The other options do not provide the necessary support for alignment. Tablet computers, for example, do not contribute to physical positioning and could even distract from the task at hand. Using only a single hand would not provide adequate control or support when repositioning a client, possibly leading to strain for both the client and the caregiver. Lastly, loose clothing, while comfortable, does not have the structural support needed to maintain proper alignment during repositioning. Thus, the best choice for maintaining proper alignment is indeed pillows and bath blankets.