Answer:
The first access control matrix:
          Alice    Bob    Cindy
alicerc      rwx       r       r
bobrc        r       rwx      rw
cyndyrc                    rwx   Â
The access control matrix after the new permissions:
          Alice    Bob    Cindy
alicerc      rwx             r       Â
bobrc        r       rwx    rw
cyndyrc      r              rwx   Â