In instruction pipelining, which hazard is primarily caused by branches?

• A. Data hazard
• B. Control hazard
• C. Structural hazard
• D. Cache hazard

Answer: (B)

Branches disrupt the smooth flow of instructions in a pipeline because the next instruction to fetch depends on whether the branch is taken or not. The decision may not be known immediately, so the fetch stage might advance along the wrong path and must be corrected once the branch outcome is resolved. This interruption is called a control hazard, since it stems from the control flow decision rather than data values or resource conflicts. By contrast, data hazards come from dependencies between instructions on data values, structural hazards from insufficient hardware resources, and cache-related delays are memory-system effects rather than a branch-specific hazard. So the branch-driven stall is a control hazard.