Answer: a. 4,700 mh
Step-by-step explanation:
Assuming:
[tex]1 mh = 10^{-3} h[/tex]
[tex]1 kh = 10^{3} h[/tex]
[tex]1 ph = 10^{-12} h[/tex]
The only option that is correct is a. 4,700 mh, let's prove it with the following conversion:
[tex]4.7 h \frac{1 mh}{10^{-3} h} = 4,700 mh[/tex]