Based on the premise "The only way to visit any of the six still active 16th-century synagogues is with a guided tour offered by the Museo Ebraico in the Campo del Ghetto Nuovo.", can we conclude the hypothesis "Anyone can visit the active 16th-century synagogues at any time." is true (see options)?

Possible answers:
(a). yes.
(b). it is not possible to tell.
(c). no.
(c).