Which of the following is the least promising method of large-scale oil extraction in the next several decades?

W) Drilling access to underground oil reservoirs [REZ-er-vawahrs]

X) Acquiring oil from whales

Y) Acquiring oil from algae

Z) Acquiring oil produced by genetically re-engineered Escherichia coli [e-schuh-ri-KEE-uh koh-LY]
X) ACOUIRING OIL FROM WHALES