What is the correct order of processes in the accretion of planetesimals?

A). Collapse, condensation, accretion, clearing.

Explanation:

Planetesimals are described as the small solid astronomical objects which are the building blocks for the formation of solid planets. Accretion is described as the process in which the solid astronomical objects cluster to form larger objects that eventually leads to the formation of planets.

As per the question, the correct order of processes that are followed in this accretion process would be a collapse, condensation, accretion, clearing. First occurs the collapse of a nebula followed by condensation of cosmic dust grains. After this, the accession or accumulation of solid parts takes place to form larger objects and this is immediately followed by the clearing of debris and dust to allow planets to form. Thus, option A is the correct answer.