A scientist is measuring the frequency of different electromagnetic waves. Which two measurements show the same frequency?
8.0 kHz8.0\text{ kHz}8.0 kHz and 80×103 Hz80 \times 10^3\text{ Hz}80×103 Hz
400 MHz400\text{ MHz}400 MHz and 4.0×108 Hz4.0 \times 10^8\text{ Hz}4.0×108 Hz
3.0 GHz3.0\text{ GHz}3.0 GHz and 3.0×1010 Hz3.0 \times 10^{10}\text{ Hz}3.0×1010 Hz
20 mHz20\text{ mHz}20 mHz and 20×103 Hz20 \times 10^3\text{ Hz}20×103 Hz