Which of the following instruments or sensors are using the direct method of level measurement?a.d/p level transmitterb.displacer level transmitterc.floatless level switchd.dipsticke.Vibrating or Tuning Fork Transmitter

The direct method of level measurement involves physically measuring the level of the substance in a container. From the options provided:

a. d/p level transmitter - This is an indirect method of level measurement. It measures the differential pressure which is then used to infer the level of the substance.

b. displacer level transmitter - This is also an indirect method. It measures the buoyant force exerted on a displacer which is then used to infer the level.

c. floatless level switch - This is an indirect method. It uses changes in electrical properties to infer the level of the substance.

d. dipstick - This is a direct method of level measurement. The dipstick is physically inserted into the substance and the level is read off the stick.

e. Vibrating or Tuning Fork Transmitter - This is an indirect method. It measures the change in frequency of a vibrating fork which is then used to infer the level of the substance.

So, out of the options provided, only the dipstick uses the direct method of level measurement.