In the following figure, rectangle represents Opticians, circle represents Curators, triangle represents Campers and square represents Europeans. Which set of letters represents Opticians who are either Europeans or Campers?
In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No error'. The reason for (1)/ his failure is because (2)/ he didn't study at all. (3)/ No Error (4)