Calculate Rate Problem: Converting 3 Cookies Per Minute to Hours

To solve this problem, we'll go through the following steps:

• Step 1: Convert the time from hours to minutes.
• Step 2: Calculate the total number of cookies eaten using the rate of eating.

Now, let's work through each step:

Step 1: Convert the time from hours to minutes. Since there are 60 minutes in an hour, the time span in minutes is $60$ minutes.

Step 2: Calculate the total number of cookies. Darío's eating rate is $3$ cookies per minute. Multiply the eating rate by the total time in minutes to find the total number of cookies eaten:

Therefore, Darío eats a total of $180$ cookies in one hour.

This matches the given correct answer choice. Thus, the solution to the problem is $180$.