In the following passage, some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.
To know ______ reality, the powers of the mind need to be turned back upon itself. With concentration, the mind can ______ its innermost secrets, just as the darkest places reveal their secrets to the penetrating rays of light. We can then ______ soul truths, whether life exists for five minutes or for ______, and whether there is a God. To go beyond the mind and our present reality, we need to use the mind itself as a tool. Patanjali, in his Hatha Yoga Pradipika, stated, “Yoga is the ______ of the modifications of the mind.”