To "proliferate" means to:

The term "proliferate" specifically refers to the rapid increase or multiplication of something. It is often used in contexts such as biology, where it describes the quick reproduction of cells or organisms. The essence of proliferation is the notion of growth happening at a swift pace, leading to a significant rise in quantity or number. This concept aligns perfectly with the choice that indicates causing something to grow or increase rapidly.

The other options present meanings that do not capture the essence of the term. For instance, reducing in size or amount directly contradicts the idea of proliferation. Likewise, moving from one location to another does not pertain to the growth aspect emphasized by the term. Creating complex structures involves a different process altogether, focusing more on development than on quantity increase. Therefore, the correct understanding of "proliferate" centers on its definition related to rapid growth and increase.