from the list below, select four situations in which casting is the preferred fabrication technique. (1) for alloys having low ductilities (2) when it is the most economical fabrication technique (3) when it is needed to join a large variety of metals and alloys (4) for large pieces and/or complicated shapes (5) for economical producing of parts that require very close dimensional tolerances (e.g. bushing and gears) (6) when mechanical strength is not an important consideration (2), (3), (5), (6) (1), (2), (4), (6) (2), (3), (4), (6) (1), (2), (4), (5) (1), (3), (4), (5)