A student monitoring the products of an organic reaction records the following mass spectrum of a purified product.

Which carbon compound produced this mass spectrum?
C4H9+\text{C}_4\text{H}_9^+C4H9+
C3H8\text{C}_3\text{H}_8C3H8
C4H10\text{C}_4\text{H}_{10}C4H10
C3H7+\text{C}_3\text{H}_7^+C3H7+