Primary succession takes much longer time than secondary succession, because it involves

The correct option is A development of a seed bank
Primary succession is a process of gradual changes in the ecosystem, that starts where no living organisms are there e.g., bare rock, newly created pond or reservoir.

In this period weathering of rocks and formation of soil takes place which is time-consuming process. Whereas secondary succession occurs in areas that somehow, lost all the living organisms, that existed there.

Secondary succession begins in areas where natural biotic communities have been destroyed, such as in abandoned farmlands, burned or cut forests, lands that have been flooded.

Since some soil or sediment is present, secondary succession is faster than primary succession.