steel pipe is usually connected with fittings that are _____.\ngrooved\nthreaded\nsoldered\nwelded

Brief Explanations:

Steel pipes are commonly connected using threaded fittings. Threaded connections are practical for steel pipes as they allow for easy assembly and disassembly when needed. Grooved fittings are more for larger - diameter pipes in fire - protection and some industrial systems. Soldering is not suitable for steel as it is a ferrous metal and soldering is mainly for non - ferrous metals like copper. Welding is a more permanent and often used for large, stationary steel pipe systems but not as common as threaded for general applications.

Answer:

B. threaded