Answer :
The name of period that has the digits 913 is hundreds.
Because Period is considered to a group of places of the digits.
In this case, the given number is 913 and it is the group of hundred because 900 is the highest number it contains.
We can also write 913 as
913 = 900 + 10 + 3
It means,
9 hundreds + 10 tens + 3 ones