Piston rings should be installed so that the trademarks or dots:

The correct approach for installing piston rings is to ensure that the trademarks or dots should face the top of the piston. This alignment is crucial for proper functioning of the piston rings. The markings typically indicate the orientation that the manufacturer has determined to be correct for optimal sealing and performance.

Installing the rings with the markings facing upwards maintains the integrity of the ring's design and ensures that the oil control functionality is appropriately executed. If the rings are installed incorrectly, it can lead to less effective sealing between the piston and cylinder wall, which can result in increased oil consumption, poor engine performance, and potential failure over time.

The other options may suggest different orientations that do not align with the manufacturer's specifications and could lead to complications in engine performance and longevity. Hence, it is essential to follow the guideline of having the trademarks face the top of the piston.