Option 1: 1973 - This option is the correct answer. The Name of the Laccadive, Mini-coy, and Amindivi Islands was changed to Lakshadweep by an act of parliament in 1973.
Option 2: 1970 - This option is incorrect. The correct year when the name change occurred is 1973, not 1970.
Option 3: 1971 - This option is incorrect. The correct year when the name change occurred is 1973, not 1971.
Option 4: 1972 - This option is incorrect. The correct year when the name change occurred is 1973, not 1972.
Therefore, the correct answer is option 1, 1973.