Solution
= Solution
{c}
The <Euclidean algorithm> gives
$$
\begin{aligned}
497&=259+238,\\
259&=238+21,\\
238&=11\cdot21+7,\\
21&=3\cdot7.
\end{aligned}
$$
The last nonzero remainder is the <greatest common divisor>, so $\boxed{\gcd(259,497)=7}$.
= Solution
{c}
The <Euclidean algorithm> gives
$$
\begin{aligned}
497&=259+238,\\
259&=238+21,\\
238&=11\cdot21+7,\\
21&=3\cdot7.
\end{aligned}
$$
The last nonzero remainder is the <greatest common divisor>, so $\boxed{\gcd(259,497)=7}$.