Symbioses Involve the Process of Co-Evolution of at Least Two

Symbioses involve the process of co-evolution of at least two species. Which is a characteristic of co-evolution?

A) ongoing evolutionary change to the genome of one species (affector) , while the other species' (driver) genome does not change
B) ongoing evolutionary change in each species in response to the other species involved in the symbiotic partnership
C) periods of rapid evolutionary change punctuated by periods of stasis
D) simultaneous evolution within the genomes of an organism and an endosymbiont organelle