In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.

Challenges are (1)__________ that knock on our door. It may sound difficult to (2)_____________ the obstacles in our career but challenges are rewarding. If there were no challenges there would have been no (3)__________ on this planet. Every challenge poses as an opportunity for those who like to put their (4)________ to the fullest utilisation. Knowledge and (5)_________ is the key to overcome challenges.