Guillermo spends some time each day applying the principles of structuralism to examine his own conscious experience as carefully as possible. guillermo is engaged in -centered

The fact that Guillermo spends some time each day applying the principles of structuralism to examine his own conscious experience as carefully as possible means that Guillermo is engaged in introspection.  Introspection is exercise used in psychology that involves thinking about and analyzing your own thoughts and behaviors.
This act of self-awareness is very important.

The answer is c) protestant clergy