In Data structure, main characteristic of “ring” is : A. last, record points to the first record B. first record points only to the last record C. many records point to one record D. All of the above E. None of the above

The correct answer is: A. last, record points to the first record.

A ring is a data structure in which the last record points to the first record, forming a circular chain. This means that there is no beginning or end to the data, and you can access any record in the ring by starting at any record and following the pointers.

Option B is incorrect because the first record does not point only to the last record. It points to the second record, which points to the third record, and so on.

Option C is incorrect because there are not many records pointing to one record. There is only one record pointing to the first record, and the first record points to the last record.

Option D is incorrect because only option A is correct.

Option E is incorrect because option A is correct.