Comprehension:In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.The road to success is not 1________ ; there is a curve called failure, a loop called confusion, speed bumps called friends, caution-lights called family, and you 2 ________ have flats called jobs. But 3 ________ you have a spark called determination, an engine called perseverance, insurance called faith, and a driver called God, you will make it 4 ________ a place called success!In spite of all our planning and preparation, 5 ________ challenges are certain to arise.Select the most appropriate option to fill in blank number 4.

1. A
   to
2. B
   although
3. C
   until
4. D
   through