Question: You have a matrix `data` in which each column is mono audio recording from a room in your house. You've noticed that each column has a very different mean and when you plot them all on the same graph, the spread across the y axis make it impossible to see anything. You want to subtract the mean from each column. Which code block will accomplish this?

1. [ ]
2. [x]
3. [ ]
4. [ ]

Answer: The correct answer of the above question is Option B:[x]