Given below are some words from an artificial language.
agnoscrenia means poisonous spider
delanocrenia means poisonous snake
agnosdeery means brown spider
Which of the following is most likely to mean “black widow spider”?

(1) agnoscrenia means poisonous spider
(2) delanocrenia means poisonous snake
(3) agnosdeery means brown spider

From statement (1) and (2) we can say that crenia here refers to 'poisonous'.
From statement (1) and (3) we can say that agnos here refers to 'spider'.
From statement (1) and (2) we can say that delano here refers to snake. 

"black widow spider" will definitely consist code agnos. Hence, only option B or C can be correct answer. 

'delano' can't be code for "black widow" because delano refers to snake. Hence, option B is the correct answer.