ANS:A - an ordinary chain

The chain is used for measuring and layout of survey lines. Cloth and the metallic tape are used for measuring short offset distance while former for more accuracy. The steel tape is used for checking chain length and invar tape is used for very accurate measurements such as the base line. Invarted tape is used for measuring short offset distance while former for more accuracy. Chain is also used for the measurement of base line. Because Invar tape have low thermal expansion.