Answer:
c
Step-by-step explanation:
A has 9 sig digits. Every digit counts including the 4 zeros, because 3 digits follow them. Even if the 345 were not there, there still are 6 sig digits.
B. Those two trailing zeros mean something. They are guaranteed place holders. This number has 7 sig digs.
D. Depends on who teaches this. 5 without a period at the end means that the number is exactly 5 -- or that's the rule when I was teaching.
The answer is C, believe it or not. Again, those zeros are place holders. They are guaranteed to be accurate. This is a question to look at carefully.
