Find the odd number from the given alternative.

In this classification question, each number follows a digit-sum rule: the sum of the 1st, 3rd, and 4th digits (counting from the left) must equal the 2nd digit. The number that breaks this rule is the odd one out.

1. 5720 -> digits are 5, 7, 2, 0. Sum of the first, third, and fourth digits: 5 + 2 + 0 = 7, which equals the second digit (7) -- the pattern holds.

2. 6710 -> digits are 6, 7, 1, 0. Sum: 6 + 1 + 0 = 7, which equals the second digit (7) -- the pattern holds.

3. 2640 -> digits are 2, 6, 4, 0. Sum: 2 + 4 + 0 = 6, which equals the second digit (6) -- the pattern holds.

4. 4270 -> digits are 4, 2, 7, 0. Sum: 4 + 7 + 0 = 11, which does NOT equal the second digit (2) -- the pattern breaks.

Rechecking, the pattern holds consistently for the other three numbers (5720, 6710, 2640), while 4270's sum (11) does not match its second digit (2) -- confirming 4270 is the number that breaks the pattern.

Therefore, 4270 does not follow the pattern, making it the odd number out.