It's known that 60 % of restaurant customers add ketchup to their meat dish and 50 % of restaurant customers add mustard to their meat dish. It's also known that 70% of restaurant customers add at least one of two ingredients to their meat dish.

a. The probability that randomly selected restaurant customer adds both ingredients (ketchup and mustard) to their meat dish is _____________.

b. If it's known that one particular restaurant customer adds ketchup to meat dish, then probability that this customer adds mustard to the meat dish is ________________.

c. Can we say that the events of adding ketchup to the meat dish and the event of adding mustard to the meat dish by the same randomly selected customer are independent events? Answer Yes or No. _____________________