Step 1
Standard notation of a number is when a number is written with only number digits and not in scientific notation.
E.g 1235679 is in standard notation
1.235679 x 10^6 is in scientific notation
Step 2
Write 6.43 x 10^7 in standard notation
[tex]\begin{gathered} 10^7=\text{ 10000}000 \\ 6.43\text{ x 10000000= 64,300,000} \end{gathered}[/tex]
Hence the answer is option B
