Suppose that cats' weight in the East York Animal Shelter follows a normal distribution with a mean of 18 kg and a variance of 0.25 kg^2. Which of the following R functions is used for obtaining the probability that a randomly chosen cat weighs more than or equal to 20kg? Question 1 options: 1-pnorm(20,18,0.50) pnorm(19,18,0.25,lower.tail=FALSE) 1-pnorm(20,18,0.25) pnorm(19,18,0.5,lower.tail=FALSE)