At a local veterinary office, 48% of dogs get their teeth cleaned, while 35% of cats get their teeth cleaned. Let po and pc be the sample proportions of dogs and cats at this veterinary office, respectively, who get their teeth cleaned. Suppose 25 dogs and 32 cats from this veterinary office are selected at random to collect data on their teeth-cleaning history. Which of the following is the correct calculation and interpretation of the standard deviation of the sampling distribution of p(d)-p(c)​