Depend on your ambition as a police officer and where you pass your classes.
Mostly brain fields to pass your classes and be in the top of the classement.
Sport fields, specially endurance fields like Kinesthetic Fields if you wants to be in a elite intervention unit as some test are really hard.
Also brain fields again to take quick and accurate reaction. Thats part of some police test.
Manhattan method, conceptual conglomerate, opus Manhattan
Also Ojas at first to get the proper fuel at the beginning of your day.
Also fields to avoid stress and be resilient.
Last field could be one to purify yourself before sleeping, or a shield.