Please choose the correct ending to complete the given sentence: Work World: [header] How to become a diesel mechanic [title] Prepare for a diesel mechanic career while still in high school. [substeps] Study hard on the career path you would like to take before committing 100 %. Obtain a high school diploma.

Ending1: Make sure you have a clean tank and transponder. Enlist in activities that require a high school diploma; for example, mowing lawns is extremely rewarding and will provide lots of support for young diesel engineers. Ending2: Complete a 4-year bachelor's degree. Gain practical experience in road work, construction, gas, diesel, farming, and racquetball. Ending3: You will need to be 21 years of age or older if you want to become a diesel mechanic. Preparing for high school will help you meet industry milestones. Ending4: Take classes that will enhance your knowledge on your topic. [title] Enroll in a college or vocational program that offers a diesel mechanic certificate or associate's degree program.

Answer format: ending1/ending2/ending3/ending4