Section 775. Defenses

It shall be a sufficient defense to the proceeding,
  if the owner or any mortgagee or lienor of record establish that:
    a. The condition or conditions alleged in the petition did not in fact
  exist or  that  such  condition  or  conditions  have  been  removed  or
  remedied; or
    b.  Such  condition  or  conditions  has  been caused by a petitioning
  tenant or  tenants  or  members  of  the  family  or  families  of  such
  petitioner  or  petitioners  or of their guests or by other residents of
  the dwelling or their families or guests; or
    c. Any tenant or resident of the dwelling has  refused  entry  to  the
  owner  or  his  agent  to  a  portion of the premises for the purpose of
  correcting such condition or conditions.