Question

why is 2.6 billion a significant number regarding the 2016 u.s. elections? it was how many people the election was expected to affect worldwide. it was the amount of money spent on presidential campaign media. it was the 2016 annual defense budget.

Explanation:

The 2016 U.S. presidential election's campaign media spending reached approximately $2.6 billion, making this the correct link. The global population affected would be far larger than 2.6 billion, and the 2016 U.S. defense budget was over $600 billion, so those options are incorrect.

Answer:

It was the amount of money spent on presidential campaign media.