I have to disagree with daveatc...
Hard altitudes are routinely assigned to VFR aircraft in Class B and Class C airspace, as are headings and, sometimes, routes. The altitude assignments must meet the MVA, MSA and minimum IFR altitude criteria. That, in theory anyway, takes care of running into mountains. VFR pilots are expected to advise ATC if any clearance, instruction, altitude, route or heading assignment will prevent them from complying with the applicable CFR. So cloud clearance responsibility remains with the pilot.