A programmer is writing a software application about birds that will use a variety of data sources. They want to understand which data sources are analog so that they can think carefully about the process of converting the analog data into digital data.

Which of these data sources is analog?

Choose $1$ answer:

Choose $1$ answer:

$($Choice A$)$ The altitude of a bird as it flies through the sky

A

The altitude of a bird as it flies through the sky

$($Choice B$)$ The number of reported sightings of a particular bird species in each zip code

B

The number of reported sightings of a particular bird species in each zip code

$($Choice C$)$ A list of birds that are most commonly seen in a particular park

C

A list of birds that are most commonly seen in a particular park

$($Choice D$)$ The average length of the songs sung by a particular bird

D

The average length of the songs sung by a particular bird