Just need the answers and help to understand.

2. Carmine is creating a schedule for five key presenters who will be speaking to students on career day. They have hired a doctor, an engineer, a pilot, a lawyer and an accountant. What is the number of possible arrangements of speakers if: (each question is a new scenario, they do not stack) a) if there are no restrictions? b) the doctor must speak first? c) the engineer and pilot must speak one after the other? d) the lawyer and accountant are not to follow one another? Part B: Communication 1. High school students often use a combination lock to lock their lockers. Why is the term "combination lock" a poor choice of words? What would be a better name? Provide an example to help aid your explanation. Part C: Application 1. Ontario License Plates consist of 4 letters followed by 3 letters. Assuming that all letters and numbers can be used more than once, how many license plates are possible? 2. YRDSB's Summer E-Learning is selecting a student committee! 8 boys and 6 girls have been nominated to be chosen for the committee. If the committee consists of 4 students, then how many ways can the committee be chosen if... a) There are no restrictions. b) At least one boy must be on the committee. 3. You are packing some snacks for a picnic with your friends. In your fridge, you have 2 bananas, 6 cheese strings and 9 juice boxes. If you choose 5 items, what combinations of snacks can you bring if you must bring at least one banana? 4. What is the probability that there are at least two people with the same birthday in a class of 32 students