The answer is C - a mixed composition house is likely to have the lowest homeowners insurance premiums.
Steel and all-brick homes are typically more expensive to insure because they are more resistant to damage from extreme weather events like storms and tornadoes.
All-wood homes are more susceptible to damage from fire, which can be more expensive to fix.
On the other hand, mixed composition homes have a combination of materials, which can provide protection against both extreme weather events and fire, making them less expensive to insure.