For this case we can do the following operation:
[tex]0.7x10^4x2[/tex]
We can put together 2 and 0.7 using the distributive property and we got:
[tex](0.7\cdot2)x10^4[/tex]
And finally we got:
[tex]1.4x10^4[/tex]
And the best answer would be the first one.
