One nanometer is equal to 10^-7 cm.
Option 1: 10^-7 cm - This option correctly represents one nanometer. The negative exponent indicates that the value is a decimal fraction of a centimeter.
Option 2: 10^6 cm - This option represents one micrometer (also known as a micron), which is equal to one millionth of a meter, not one nanometer.
Option 3: 1CT4 cm - The "CT" in this option seems to be a typo or an unclear value. There is no recognized conversion factor that uses "CT" in relation to centimeters.
Option 4: 1CT3 cm - Similar to option 3, this option also includes the unclear value "CT" in relation to centimeters.
Overall, option 1 is the correct answer as it accurately represents the value of one nanometer. Alert - correct answer should be option 1.