Generally brute force, or understanding what the language is.
In the question, as far as I can understand, the language $a^{2m + 1}b^{2n + 1}$ is Odd number of $a’s$ followed by some odd number of $b’s$ and those odd numbers will be greater than $1$ as $m$ and $n$ cannot be 0.
Since, the length 10 is asked, what odd numbers we can take?
$\{3, 5, 7, 9\}$
And how can we make $10$ from selecting $2$ numbers independently ? (because $m$ and $n$ have no relation with each other)
$a^7b^3, a^5b^5, a^3b^7$
These $3$ strings can be made.
