Of those four, only (C) "coolly" is spelled correctly.
Coolly is spelled correctly. Procede should be proceed. Superintendant should be superintendent. Arguement should be argument.
The correct spelling of the number "14" is, indeed, "fourteen." The number "40," however, is spelled "forty."
Yes it is spelled correctly
You have spelled 'still' correctly.
No word is always spelled correctly. But the word "correctly" is correctly spelled as correctly. (see related question)
Yes, surprisingly is spelled with an S. Surprisingly is how you spell it. You spelled it correctly.
Yes, you have spelled prosperous correctly.
You've spelled it correctly.
You spelled it correctly..
Convenience (easy access or availability) is correctly spelled.
Yes, engineer is spelled correctly in your question.