Natural numbers that divide both $346$ and $556$ leaving remainder $31$ are common factors, greater than $31$, of $315$

Question

Natural numbers that divide both $346$ and $556$ leaving remainder $31$ are common factors, greater than $31$, of $315$ and $525$. That set is—

Accepted Answer

$\{35, 105\}$

Answer

$\{35\}$

Answer

$\{35, 63, 105\}$

Answer

$\{105\}$

Natural numbers that divide both 346346346 and 556556556 leaving remainder 313131 are common factors, greater than 313131, of 315315315 and 525525525. That set is—