Choose or find odd pair of words - (Shopkeeper : Customer) , (Doctor : Patient) , (Lawyer : Client) , (Clerk : File)

D. CLERK : FILE

Choose or find odd pair of words - (Daring : Timid) , (Beautiful : Pretty) , (Clear : Vague) , (Youth : Adult) , (Native : Alien)

B. BEAUTIFUL : PRETTY

Choose or find odd pair of words - (Principal : School) , (Soldier : Barrack) , (Artist : Troupe) , (Singer : Chorus)

A. PRINCIPAL : SCHOOL

Choose or find odd pair of words - (Onomatology : Names) , (Nidology : Nests) , (Phycology : Algae) , (Concology : Shells)

D. CONCOLOGY : SHELLS

Choose or find odd pair of words - (Pyroheliometer : Radiation) , (Calorimeter : Humidity) , (Planimeter : Area) , (Barometer : Humidity)

D. BAROMETER : HUMIDITY