In the article on "Blooms Taxonomy", according to the pyramid showing how much you are likely to remember, which leads to the highest level of retention?

According to Blooms Taxonomy, the highest leves of retention it's achieve when: Teaching the material to others.

Explanation:

Teaching the materials to others is the most efficient way to retein and learn, because this way a person explains to others and to himself the infromation. It allows clarity of thoughts, making clear statements and preparing the information to be able to explain it.