Final answer:
Open sights are standard on most handguns, which compensate for gravity. A gun sighted for 100 m will show a drop in trajectory at 150 m. Increasing muzzle velocity leads to a flatter trajectory, less drop, and air resistance affects bullet drop.
Step-by-step explanation:
The type of firearm sight that is simple, inexpensive, and standard on most handguns is c) Open sights.
Guns are sighted to compensate for the effect of gravity, allowing for accuracy at certain ranges. For a gun sighted for 100.0 m and fired at a target 150.0 m away, there will be a noticeable drop in the bullet's trajectory due to gravity. If the muzzle velocity is 275 m/s, this drop can be calculated using ballistic equations.
Increasing the muzzle velocity would result in a flatter trajectory over the same distance, resulting in a lesser drop and potentially a more accurate shot at longer ranges. Additionally, air resistance has the effect of slowing down the bullet, which over time, increases the bullet drop.
However, quantifying this without specific air resistance coefficients is complex and requires more detailed information.