4. filing a certificate of insurance

How would the previous sentence be correctly capitalized?
Answer: 4. Filing a certificate of insurance
he also posed a generalisation of the continuum hypothesis by asking if 2 to the power a was equal to a+1.

How would the previous sentence be correctly capitalized?
Answer: He also posed a generalisation of the continuum hypothesis by asking if 2 to the power a was equal to a+1.
a major reworking of the instruments for humanitarian aid

How would the previous sentence be correctly capitalized?
Answer: A major reworking of the instruments for humanitarian aid
did someone email you a tcd file and you're not sure how to open it? maybe you have found a tcd file on your computer and wondering what it's for? windows might tell you that you can't open it, or in the worst case, you might encounter a tcd file related error message.

How would the previous sentence be correctly capitalized?
Answer: Did someone email you a TCD file and you're not sure how to open it? Maybe you have found a TCD file on your computer and wondering what it's for? Windows might tell you that you can't open it, or in the worst case, you might encounter a TCD file related error message.