Please choose the correct ending to complete the given sentence: Work World: [header] How to become an aerospace engineer [title] Develop sound math and science skills in high school. [step] Aerospace engineering requires advanced science and math skills. Take classes in chemistry, physics, algebra, calculus, and trigonometry in high school to get a head-start on developing the skills you'll need.

Ending1: Some four-year colleges offer pre-schooling courses in engineering. Some high schools offer an all-family education program which focuses on automobile mechanics, mechanical engineering, and physics. Ending2: [substeps] You should be at least 18 years old when you begin your aerospace engineering career. You can get an an a in about five years. Ending3: [title] Speak with your teacher about whether engineer training is right for you. [step] If you need to grow intellectually, the best way to do so is to find a training location. Ending4: [substeps] Put your best effort into these classes so you can earn high marks. A high gpa will help you get into a good aerospace engineering program in college.

Answer format: ending1/ending2/ending3/ending4