Which contains an independent clause?

because the tragic fumble was scored by the visiting team in the last minute.
when the player, in an extraordinary move, went charging down the field.
as the uproar from the delirious fans exploded jubilantly through the stadium.
while the team made their play, the frenzied crowd cheered them to victory.

While the team made their play, the frenzied crowd cheered them to victory.

This is a good example showing a main clause and it subordinate counterpart. IF let alone, the section underlined stands as a whole sentence and clearly expresses an idea. complies to having its subject, verb, etc. While the section in itallics is complementary, therefore subordinated and dependant to the underlined sentence.

Imagine reading While the team made their play... If let alone, the expression would reflect something is missing, hence an incomplete idea is then solved by adding the second part. ...the frenzied crowd cheered them to victory. Finally we see the ideas forming a whole.

it was given away at no charge

the bottom of the ocean