In my opinion, mental health can affect all of these options. However, I think the answer this is looking for would be "A person's ability to breathe"
Mental health definitely affects motivation; and motivation affects mental health. Motivation is a driving force behind human behaviours; its absence can lead to mental illnesses such as depression. Often when someone is depressed, they lack the motivation to do things.
Mental health can affect decision making as well- for example, if someone has anxiety, decision-making can be harder. Anxiety disrupts the decision-making regions in the prefrontal cortex.
Mental health can also affect memory- Depression has been linked to memory problems, such as forgetfulness. Depression is associated with short-term memory loss. Stress and anxiety can also lead to poor memory.
I would say that panic attacks can inhibit a person from breathing, but considering the options I would say that's the best one. Breathing is more of a physical thing, not associated with the brain or mental condition. So the answer is A person's ability to breathe.