Debug the following R code $($the original question is in the screenshot.$)$

The code: $"$# Load necessary libraries

library$($dplyr$)$

# Import the data

data read.csv$("$data$/$measles$.$csv$")$

# Compute the number of rows with missing values in the 'rate' column

numNA sum$($is$.$na$($data$rate$))$

# Print the number of missing values

print$($numNA$)$

# Remove rows with missing values in the 'rate' column

data$\_$clean data $\%>\%$ filter$(!$is$.$na$($rate$))$

# Define the years of interest

years$\_$of$\_$interest c$(1930,1940,1950,1960,1970,1980,1990,2000)$

# Compute the median rate for the specified years after removing missing values

medianRateNA sapply$($years$\_$of$\_$interest, function$($year$)\{$

median$($data$\_$clean$rate$[$data$\_$clean$year $==$ year$],$ na$.$rm $=$ TRUE$)$

$\})$

# Compute the mean rate for the specified years after removing missing values

meanRateNA sapply$($years$\_$of$\_$interest, function$($year$)\{$

mean$($data$\_$clean$rate$[$data$\_$clean$year $==$ year$],$ na$.$rm $=$ TRUE$)$

$\})$

# Replace missing values in the 'rate' column with zero

data$rate$[$is$.$na$($data$rate

# Compute the median rate for the specified years after replacing missing values

medianRate sapply$($years$\_$of$\_$interest, function$($year$)\{$

median$($data$rate$[$data$year $==$ year$])$

$\})$

# Compute the mean rate for the specified years after replacing missing values

meanRate sapply$($years$\_$of$\_$interest, function$($year$)\{$

mean$($data$rate$[$data$year $==$ year$])$

$\})$

# Print results

print$($medianRateNA$)$

print$($meanRateNA$)$

print$($medianRate$0)$

print$($meanRate$0)"$

And now the bug:

"Code execution failed with error:

Error in eval$($ei$,$ envir$)$: exists$("$numNA$")$ is not TRUE"