2.1 OSPF Filtering out stub network???

In 2.1 it states we need to filter out LSA's so they are not sent out stub networks.  This question makes no sense to me.  The answer has use filtering all LSA's out FA0/1 on R3.  That interrace belongs to Area 0.  What are they trying to show us here?

2.1 

Rack1R3#sh ip ospf int br

Interface    PID   Area            IP Address/Mask    Cost  State Nbrs F/C

Fa0/1        1     0               130.1.33.3/24      1     DR    0/0

Lo0          1     345             150.1.3.3/24       1     LOOP  0/0

Se1/1        1     345             130.1.35.3/29      781   BDR   1/1