Correct option is D
In engineering drawing, a surface finish symbol with a circle indicates that no material removal (machining) is allowed on that surface. This means the surface must remain in its original form, such as cast, forged, or rolled condition. This is important when machining could damage the surface properties or when finishing is unnecessary. Other options refer to machining processes like grinding or general material removal, which are represented by different symbols. Therefore, the presence of the circle specifically denotes prohibition of machining, making option d correct.
