Which of the following address(es) the problems posed bychromatin during transcription?

a) In some instances, protein factors can interfere withchromatin structure at specific locations, opening sensitivesites.

b) The action of chromatin remodeling factors is involved, whichrequire ATP hydrolysis to allow the promoter regions to accept thecomplex.

c) In some cases, chromatin structure rearranges at the time ofreplication.

d) All of the listed statements are true.