The correct answer is C) The cargo block is raised and lowered by the luffing winch. The cargo block is raised and lowered by the hoisting winch, not the luffing winch. The luffing winch is responsible for raising and lowering the crane jib, which is the boom or arm of the crane. The hoisting winch controls the movement of the cargo block, which is the hook or attachment that lifts the load. The other options are incorrect because A) and B) correctly describe the functions of the hoisting winch and luffing winch, respectively, while D) is a catch-all statement that is not true since one of the options is indeed false.