How many numbers between 10 and 13000, when read from left to right, are formed by consecutive digits in ascending order? For example, 456 is one of these numbers, but 7890 is not.
(a) 10
(b) 13
(c) 18
(d) 22
(e) 25
The correct option is (d).

The numbers in question, with

- two digits, are 12, 23, 34, 45, 56, 67, 78, and 89 (8 numbers);
- three digits, are 123, 234, 345, 456, 567, 678, and 789 (7 numbers);
- four digits, are 1234, 2345, 3456, ..., 6789 (6 numbers);
- finally, with five digits, only 12345,

for a total of $8+7+6+1=22$ numbers.