Answer: 838 x 10^5
Step-by-step explanation: We first have to focus on the Zambezi which is 83,800,000 there are 5 zeros, but we have three options 8.38 x 10^7, 83.8 x 10^6, and finally 838 x 10^5, but scientific notation includes no decimals so it is 838 x 10^5.