In this sutra, complete freedom is given to the person who is meditating. A person can meditate on anything that he desires, which elevates him. This is the kind of flexibility provided in the yoga, that a person can choose anything that elevates him or makes his mind calm. The ultimate objective should be that the mind should become calm by the object of meditation. A person may try each one of the above-mentioned methods and try to meditate, whatever fits his personality he can select it and continue to meditate. For me meditating on breathing is quite suitable. Developed this technique after a lot of practice indeed.