Electromagnetic spectrum — practice question

A radio transmitter emits waves with a frequency of $200\,\text{kHz}$. What wavelength do these radio waves have?

• A$6.7\times10^{-4}\,\text{m}$
• B$1.5\,\text{m}$
• C$1.5\times10^{3}\,\text{m}$
• D$1.5\times10^{6}\,\text{m}$