An engineer is attempting to improve OSPF network performance and discovers that the entire SPT recomputes whenever a type 1 or type 2 LSA is received within
an area. Which action can optimize SPT operations?

A.
Tune LSA throttling thresholds

B.
Enable incremental SPF

C.
Configure totally stubby areas throughout the domain

D.
Summarize networks on all ABRs

Explanation:
https://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/ospfispf.html#wp1027184
“Benefits of OSPF Incremental SPF OSPF uses Dijkstra’s SPF algorithm to compute the shortest path tree (SPT). During the computation of the SPT, the shortest
path to each node is discovered. The topology tree is used to populate the routing table with routes to IP networks. When changes to a Type-1 or Type-2 link-state
advertisement (LSA) occur in an area, the entire SPT is recomputed. In many cases, the entire SPT need not be recomputed because most of the tree remains
unchanged. Incremental SPF allows the
system to recompute only theaffected part of the tree. Recomputing only a portion of the tree rather than the entire tree results in faster OSPF convergence and
saves CPU resources. Note that if the change to a Type-1 or Type-2 LSA occurs in the calculating router itself, then the full SPT is performed.
Incremental SPF is scheduled in the same way as the full SPF. Routers enabled with incremental SPF and routers not enabled with incremental SPF can function in
the same internetwork.”