Answer:
A
Step-by-step explanation:
The supply of oil in Texas decreased from its supply fifty years ago because oil is a nonrenewable resource.
A nonrenewable resource is one that cannot be replenished naturally at the same pace as its usage and hence, decreases and eventually gets exhausted with usage or exploitation over time. This is unlike renewable energy resource that gets replenished even with usage.
The more the oil in Texas is exploited, the more its supply or reserve will decrease. This is why the supply of oil has decreased from what it is fifty years ago.
The correct option is A.