The time (in minutes) it takes to assemble a product is left-skewed with a mean of $20$ and a standard deviation of $6$. If random samples of size $36$ are selected, what is the shape of the sampling distribution of the sample mean?

A left-skewed distribution with a mean of $20$ and a standard deviation of $6$

A normal distribution with a mean of $20$ and a standard deviation of $1$

A right-skewed distribution with a mean of $20$ and a standard deviation of $6$

A normal distribution with a mean of $20$ and a standard deviation of $6$