I basically guessed this. Can someone check which answers are right and wrong and show the work for the right answer to each one? I'd appreciate to better understand it.

Multiple Choice: Circle the letter corresponding to the best answer choice. 1. Sarah has her core classes selected. She has 4 periods remaining in which she may take electives. Sarah has a lot of interests and is having trouble deciding between 10 different electives. Because she attends a very large high school she is able to take any of the 10 electives during any of the 4 available periods. How many different schedules could she make? a. 10,000 b. 1000 C. 5040 d. 40 2. Phone numbers take the form of a 3-digit area code, followed by a 3-digit number then a 4-digit number. How many possible different phone numbers are there? a. 100 billion b. 100 million 1 2 3 14 5 8 9 c. 10 million d. 10 billion 3. A family is planning a vacation to Disney World in Orlando, Florida. They want to spend one day at each of the parks: Magic Kingdom, Epcot, Disney's Hollywood Studios, Disney's Animal Kingdom Park, and the Water Park. In how many different orders can they visit each of these parks? a. 3125 b. 15 . 60 d. 120 4. An ice cream shop offers a "Make your own sundac" option. The sundae comes with vanilla ice cream, and you get to top it with your choice of 3 of 20 topping options. How many different sundaes can be made? a. 6840 b. 8000 1140 d. 60 5. A holiday bag of M&Ms contains all red and green candies. Suppose the bag contains 50 individual candies of which 22 are red and 28 are green. If you select 7 candies at random, what is the probability that 5 red and 2 green M&Ms are selected? a. 0.0145 b. 0.1825 C. 0.0997 d. 0.1252