The correct option is B 6567
The given sequence is 2123 , 3234, 4345, 5456, _____.
We split the above sequence into four.
The sequence of the digits in the thousands place is 2, 3, 4, 5. Hence, the next term should be 6.
The sequence of the digits in the hundreds place is 1, 2, 3, 4. Hence, the next term should be 5.
The sequence of digits in the tens place is 2, 3, 4, 5. Hence, the next term should be 6.
The sequence of digits in the units place is 3, 4, 5, 6. So, the next number should be 7.
Considering all conditions, the next term of the sequence is 6567.