Based on the premise "There are over 60 tombs in the valley and some still yet to be discovered dating c.1490 1100 b.c. , but not all will be open on your visit.", can we conclude the hypothesis "The tombs are not available to tourists." is true (see options)?

OPT:
(A). yes.
(B). it is not possible to tell.
(C). no.
(B).