The question below consists of a set of labelled sentences. Out of the four options given, select the most logical order of the sentences to form a coherent paragraph. Now the first and most X-strata of marine origin occur above the Y-simple appearance is where Z-level of the sea in horizontal position
A and B together can do a piece of work in 36 days, B and C together can do it in 24 days. A and C together can do it in 18 days. The three working together can finish the work in