The correct answer is A. A burst of speciation
Step-by-step explanation:
Adaptative radiation is part of evolution and occurs when a single organism or species diversify into a wide range of species (speciation), this process is called "adaptative" because the speciation occurs due to changes in the environment that make challenging survival usually due to the reduction of resources available and therefore organisms change to adapt to new conditions. Additionally, in adaptive radiation, the new organisms share traits with their common ancestor but also have different and unique traits. Considering this, it can be concluded adaptative radiation a burst of speciation.