Answer:
a) 
b) 
c) 10000 programs.
Explanation:
a) We know that the frequency is the inverse of the period, so:

1μs is equal to 
so 
b) If in a second there are 2.5*10^9 cycles:

c) we have to make a conversion, we know that a program takes 100*10^(-3) milliseconds, that is, 1*10^(-4) seconds so in 1 second we can execute:

10000 programs.
The answer is B (check your privacy settings) because almost all apps and websites have privacy settings that give you some options for who is allowed to see your posts.
Also, the other three answer choices don’t really respond to the question because they are not about who sees your posts, but what your posts are about.
1. D
2. D
I hope I helped :)
Your answer is:
virtual reality
I hope this helps! :)