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Answer: C. A, B, C and D

Option C — A, B, C and D — all four statements describe genuine advantages of the lecture-cum-demonstration method.

Why C is correct: The lecture-cum-demonstration method combines verbal explanation with a live showing of the process or phenomenon. Seeing the demonstration alongside the teacher's commentary makes the concept vivid and easier to retain, giving clear and permanent knowledge (A). The visual display reduces the teacher's effort in repeated verbal explanation and clarifying doubts, thereby helping the task of the teacher (B). Watching, observing and reasoning out what is happening engages students' senses and thinking, supporting their mental development (C). Since one demonstration can be shown to the whole class with limited apparatus and time, it is also an economical method (D). Hence all four points are correct, matching option C.

Paper 1 tip: For "advantages/limitations of method" MSQs, recall that lecture-cum-demonstration is praised on four standard counts — clarity & retention, teacher-friendliness, mental engagement, and economy — so an "all of the above" key is common.