Given network 172.18.109.0, which subnet mask would be used if 6 host bits were available?

Given network 172.18.109.0, which subnet mask would be used if 6 host bits were available?

• 255.255.192.0
• 255.255.224.0
• 255.255.255.192
• 255.255.255.248
• 255.255.255.252

Explanation:
With an IPv4 network, the subnet mask is determined by the hosts bits that are required:
11 host bits required – 255.255.248.0
10 host bits required – 255.255.252.0
9 host bits required – 255.255.254.0
8 host bits required – 255.255.255.0
7 host bits required – 255.255.255.128
6 host bits required – 255.255.255.192
5 host bits required – 255.255.255.224
4 host bits required – 255.255.255.240
3 host bits required – 255.255.255.248
2 host bits required – 255.255.255.252

Exam with this question: Introduction to Networks (Version 7.0) – ITNv7 Practice Final Exam