Sentence Structure

Are these correct?

1 - ........................................ , a tiny microphone in the handset converts the sounds of your voice into a pattern of electrical signals.

a- No matter how loud their voice might be

b- When you speak into a mobile phone

c- Once they have decided to work with another operator

d- As the radio wave travelled at the speed of light

e- Having bought a new mobile phone recently

My answer is B

2- ............................................... , governments need to cooperate to build on steps already taken to prevent them.

a- If only citizens were more interested in what is going on in the country

b- Until everyone is convinced that the staff in this facility is qualified enough

c- Since terrorist activities spread across the border of the countries

d- Once people realize that they are responsible for the safety of their neighbourhood

e- Whereas most governments claim that they are struggling for peace

My answer is C