A microprogram sequencer

The correct answer is option 1.

Concept:

Micro Instructions A sequencer is a collection of all devices used to pick the next micro-instruction location.

• The micro-instruction in control memory comprises a set of bits that launch micro-operations in computer registers as well as additional bits that define how the address is accessed.
• A microprogram sequencer generates the address of the next microinstruction to be executed.
• A sequencer or microsequencer generates the addresses used to step through the microprogram of a control store.
• It is used as a part of the control unit of a CPU or as a stand-alone generator for address ranges.

Hence the correct answer is to generate the address of the next microinstruction to be executed.