Choose or find odd number pair - (42 - 4), (36 - 6), (32 - 2), (15 - 5)

A. 42 - 4

Choose or find odd pair of words - (Sahara : Africa) , (Thar : India) , (Kalahari : America) , (Gobi : Mongolia)

C. KALAHARI : AMERICA

Choose or find odd word - Euphrates , Hwang Ho , Amazon , Brahmaputra , Indus

C. AMAZON

Choose or find odd word - Taxi , Phaeton , Cart , Rickshaw , Tonga

A. TAXI

Choose or find odd word - Microscope , Telescope , Periscope , Stethoscope

D. STETHOSCOPE