An older client who practices meditation describes his experience as being in a calm, nonreactive state where he focuses on the sensations he experiences. which type of meditation does this client most likely practice?

Mindfulness Meditation

Explanation:

In Mindfulness meditation attention is paid to the surroundings i.e. where we are, what are we doing, sounds around us or thoughts i.e. quality of being Present. This Promotes calmness and a nonreactive state of mind by Practicing it regularly.  

Here also client experiences match with the outcomes of mindfulness meditation i.e. calmness and high level of focus