A router learns 172.16.0.0/16 via OSPF and an administrator then configures ip route 172.16.0.0 255.255.0.0 Null0 250. Which route will the router prefer for forwarding?

The router will prefer the OSPF route. Route preference is determined by Administrative Distance (AD). OSPF has a default AD of 110. The configured static route has an AD of 250 (specified at the end of the ip route command). Since a lower AD indicates a more trustworthy route, the OSPF route (AD 110) will be preferred over the static Null0 route (AD 250). Static routes are not always preferred over dynamic routes; their preference depends on their configured AD. Null0 interfaces do not inherently have special forwarding priority; their AD determines their preference like any other route. Equal preference would only occur if both routes had the same AD, which is not the case here.