Answer: D. a spiritual belief that employs the use of meditation to find truths.
Explanation: The definition of myticism is a religious practice or believe in which people search for truth, knowledge (even the inaccessible to the intellect), and closeness to God through meditation, contemplation and prayer. So, from the given options, the phrase that best defines "mysticism" is the corresponding to option D: a spiritual belief that employs the use of meditation to find truths.