During the Late Harappan phase, long-distance trade and writing declined, not flourished — hence statement (A) is incorrect.
Statement (B) is correct as distinctive artefacts disappeared.
(C) and (D) are also correct as the quality of house construction declined, and large public structures ceased to be built.
(E) is correct as settlements and artefacts reflect a shift towards a rural lifestyle.
Correct statements: (B), (C), (D), and (E)