Select the option in which the words share the same relationship as that shared by the given pair of words.
Relaxation : Sleep

Given: Relaxation : Sleep

Relaxation → Leads to → Sleep
Now, let's analyze the options:
Option (a);  Cure : Medicine

Both show a "Cause → Effect" relationship (Medicine causes a Cure, Relaxation causes Sleep).

This is the correct option!

Option (b); Happiness : Feeling

Happiness is a type of Feeling, not a cause-effect relationship.

Option (c);  Minute : Time

A Minute is a unit of Time, not a cause-effect relationship.

Option (d);  Sky : Rocket

A Rocket moves toward the Sky, but this is more of a directional relationship, not cause-effect.

Thus, the correct option is (a).