The sale of government surplus machinery will begin at 9 a.m. and continue until the supply lasts.
Option Elimination -
A bit of basics on the usage of "until" and "as long as" first
1. "Until":
"Until" is used to indicate the point in time when an action or event will stop or a condition will be met. It suggests that something will continue to happen or remain true up to a specific time or event.
Example 1: "I will wait here until you come back."
In this sentence, the action of waiting will continue until the person returns. As soon as the person returns, the waiting will stop.
Example 2: "She studied until midnight."
This sentence means that the person studied continuously, and their studying stopped at midnight.
2. "As long as":
"As long as" is used to express a condition that must be met for something to happen or continue. It implies that if the condition remains true, the action or event will continue.
Example 1: "You can borrow my car as long as you return it by 6 p.m."
This means the person can borrow the car but only if they return it before 6 p.m. If they don't return it by that time, they may not be allowed to borrow it again.
Example 2: "I'll support you as long as you keep working hard."
This sentence indicates that the speaker will provide support, but only if the person continues to work hard. If the person stops working hard, the support may be withdrawn.
In summary, "until" is used to indicate the point in time when an action stops or a condition is met, while "as long as" expresses a condition that must be fulfilled for something to happen or continue.
Here, "supply lasts" means the duration or period of time during which a particular supply or resource remains available or in stock. So, we'll use "as long as." Had it been "supply ends or supply is depleted," then the usage of "until" would still be okay, as that would indicate a point in time, i.e., ends or depleted. But as we can't change "supply lasts" means the duration or period of time, we need to use "as long as" and not "until."
(A) will begin at 9 a.m. and continue until the supply lasts - not ok, as discussed above.
(B) begins at 9 a.m., continuing until the supply lasts - is this a perpetual action? No. Moreover, "until" is wrong.
(C) will begin at 9 a.m. and, until the supply lasts, will continue - the same issue of "until" with supply lasts.
(D) begins at 9 a.m. and, as long as the supply may last, it continues - the same issue as B.
(E) will begin at 9 a.m. and continue as long as the supply lasts - ok.