Answer: Option (3)
Explanation: In between the year 1994 to 1996, a sum of 38 number of sink holes have been found, which could be the resultant of the mining activities carried out in those two years in that particular area
In the mining area, drilling and other construction and excavations are carried out through which the water must have percolated down to the rocks like limestone, dolomite which has the ability to get dissolve when comes in contact with water. So this huge number of sink holes have occured there in that time period.