Analysis of an unknown organic compound L produces the following results.

Elemental analysis by mass of compound L

• Carbon (C): 72.00%
• Hydrogen (H): 6.67%
• Oxygen (O): 21.33%

Mass spectrum of compound L

• Key peaks at $m/z=150$ (molecular ion peak), 105 (base peak), and 77.

IR spectrum of compound L

• Strong absorption at 1720 cm^-1
• Strong absorption at 1275 cm^-1
• Absorptions at 1600 cm^-1 and 1450 cm^-1
• Absorptions just above and just below 3000 cm^-1

Proton (${}^{1}H$) NMR spectrum of compound L

• Multiplet at $\delta =7.4-8.1ppm$, relative peak area = 5
• Quartet at $\delta =4.4ppm$, relative peak area = 2
• Triplet at $\delta =1.4ppm$, relative peak area = 3