Final answer:
The wavelength of gamma-ray emission from a supernova, measured as 3.07×10⁻¹⁵ meters, is correctly represented as a decimal by option (b) 0.00000000000000307.
Step-by-step explanation:
The correct decimal representation of the wavelength of gamma-ray emission from a supernova measured as 3.07×10⁻¹⁵ meters is 0.00000000000000307. The digit 3 in the original scientific notation is followed by 15 decimal places, where the first 14 are zeros and the 15th is the digit 7. Therefore, option (b) is the accurate representation of this wavelength as a decimal.