1.  SEDATIVE : SLEEP ::

A. challenging : knowledge
B. mnemonic : memory
C. dramatic : story
D. vocal: eloquence

Answer: Option B

Explanation:

(THIHG AND PURPOSE) A sedative acts as an aid to sleep; a mnemonic (such as V1BGYOR, a word made of the first letters of the sequential colours of the rainbow) acts as an aid to memory. (B)