In the following question below are given some statements followed by some conclusions. Taking the given statements to be true even if they seem to be at variance from commonly known facts, read all the conclusions and then decide which of the given conclusion logically follows the given statements. Statements: All buildings are towns. All towns are big. All cities are big. Conclusions: I. All big are not towns. II. Some cities are definitely towns. III. Some cities are buildings. IV. No cities is a building. Correct Answer Either III or IV follows Consider the following least possible Venn diagram, [ alt="RRB PO FT 4 6 reviewed images Q1" src="//storage.googleapis.com/tb-img/production/16/09/RRB%20PO%20FT%204_6%20reviewed_images_Q1.PNG" style="height:190px; width:248px"> Conclusions: I. All big are not towns → it’s possible but not definite, hence false. II. Some cities are definitely towns → it’s possible but not definite, hence false. III. Some cities are buildings → it’s possible but not definite, hence false. IV. No cities is a building → it’s possible but not definite, hence false. Here conclusion III and IV form a complementary pair. Hence either conclusion III or IV follows.