I'm sure some will say this is a CCNA question...

Bear with me, just seeking clarification...
But, i'm going over the CCNP BSCI Official Exam Cert Guide 4th Ed. In ch2 Q&A, it asks...
Summarize the following without over-summarizing:
- 192.168.160.0/24
- 192.168.162.0/23
- 192.168.161.0/24
- 192.168.164.0/22
It gives the ans in the appendix as 192.168.160.0/21. While this summarizes all the addresses, I'm sure it over-summarizes with 165.0, 166.0 & 167.0 included in the summary address.