The correct option is (b) α > φ
To explain: If φ > α, then torque required to lower the load will be negative. In other words, the load will start moving downward without the application of any torque. Such a condition is known as over hauling of screws. If however, φ > α, the torque required to lower the load will be positive, indicating that an effort is applied to lower the load. Such a screw is known as self locking screw.