Subject :IMO Class : Class 4

Rashi said, "I am adding 3 four-digit numbers."
Which of the following statement describes what Rashi should expect as her sum ?
(a) A three-digit sum because she is adding three numbers.
(b) A four-digit sum because she is adding four-digit numbers.
(c) She will get answer above 10,000.
(d) Either a four-or five-digit number because she may be adding numbers that could be as small as 1,000 or as large as 9,999.