Answer:
Option C 1000
Step-by-step explanation:
Given that Terry and Sandhya both found sum of four digit numbers. While Sandhya added correctly, Terry made a mistake by 1 in 1000's column.
If an error is made in 1000 column by 1, either 1 digit less was added or 1 digit more was added in 1000 column, the sum would have an error of +1000 or -1000
If she did mistake of +1 she would have got total more by 1000, or if she did a mistake of -1 total would be less by 1000
Hence answer is 1000
Option C
