Final answer:
Ethyl acetate will show 4 distinct signals on its 13C NMR spectrum, corresponding to the four different carbon environments present.
Step-by-step explanation:
The question asks how many signals will be present on the 13C NMR spectrum of ethyl acetate. Ethyl acetate has the structure CH3-COO-CH2-CH3. In its 13C NMR spectrum, carbons in different environments will give different signals. The CH3 group attached to the oxygen (O-CH2-CH3) will have one signal, the CH2 group will have one signal, the carbonyl carbon (COO) will have its unique signal, and the CH3 group attached to the carbonyl (CH3-COO) will have another. Hence, there will be a total of 4 distinct signals. Therefore, the correct answer is D. 4.