The major shortcoming of waterfall model is

Answer: the difficulty in accommodating changes after requirement analysis.

Explanation: In the waterfall model development proceeds in sequential phases (requirements → design → implementation → testing → maintenance). Once the requirements phase is finished and the project moves forward, incorporating new or changed requirements requires revisiting and redoing earlier phases. This makes changes expensive, time-consuming, and risky.

• Rework needed: design, code, and tests must be revised when requirements change.

• Late discovery of issues increases cost and schedule impact.

• Limited user feedback early on can lead to mismatches between delivered system and user needs.

Why the other choices are not correct:

• Difficulty accommodating changes after feasibility analysis: Feasibility analysis occurs earlier and is not the phase typically cited as the point where change becomes most problematic; the emphasis is on changes after requirements are set.

• The system testing: Testing is a necessary phase, not a shortcoming in itself. The criticism focuses on process inflexibility, not on having a testing phase.

• The maintenance of system: Maintenance can be impacted by earlier choices, but the primary drawback highlighted for waterfall is its resistance to changing requirements during development.