How many bits are in one gigabit?

One gigabit is defined as one billion bits. In the decimal (base 10) system, which is commonly used in networking and telecommunications, the prefix "giga-" refers to a factor of one billion (10^9). Therefore, one gigabit is equal to 1,000,000,000 bits. This is consistent with how data is commonly measured in these fields, making option B the correct choice.

The other options represent significantly smaller quantities than one gigabit. For instance, 1,024 bits is a common small-scale measure in computing, often linked to binary memory storage, while 100,000,000 bits and 10,000,000 bits are far less than the billion bits that define a gigabit.