Error Detection And Correction

Step 1: Analyzing the sentence part-by-part:
"The boat was overloaded" --- Correct usage.
"with the passengers" --- Correct usage.
"and as a result it got drowned" --- Incorrect.

Step 2: Understanding the error: Boats do not "drown"; they "sink." The verb "drown" is used for living beings (like people or animals), not for objects.

Hence, the correct phrase should be "it sank" instead of "it got drowned." Thus, the error is in part C.

Step 1: Understanding the usage: The phrase "relieved from his duties" is grammatically incorrect. The correct phrase should be "relieved of his duties."

Step 2: Analyzing each part:
(A) "Mr Rao has been" --- correct.
(B) "relieved from his duties" --- incorrect; should be "relieved of his duties."
"and is expected to be here by tomorrow." --- correct.

Thus, the error is in part B.