partition and static route

We have LTM set up with Route doamin and partition (A & B) configuration. currently Partition B with RD 2 has configured with default gateway but partiton A with RD 2 dont have any gateway configured. set up are working properly and all vips configured in Partition A are reachable from other network. IN this case how return traffic is going from VIP ? as no default gateway or route configured in partition A. does it take partition B default route ?

Thanks in Advance