To map genes of a bacterial strain, conjugation must be interrupted at given times. Suppose you ...

To map genes of a bacterial strain, conjugation must be interrupted at given times.
 
  Suppose you have Hfr cells of genotype a+b+c+d+e+strR and F cells of genotype abcdestrS and you combine these two cultures in liquid medium in four blenders at time 0. After intervals of 3, 6, 9, and 12 minutes, you turn on successive blenders. What role does the blender play in the experiment? A) serves as a culture container only
  B) acts as a mechanism to bring cells into contact
  C) speeds up molecular movement of DNA
  D) shears the sex pili of conjugants
  E) hastens conjugation events