Final answer:
Option A, 'Lewis and Clark and their team began their westward expedition in St. Louis in 1804.' is a complete sentence because it has a subject and a verb phrase and expresses a complete thought.
Step-by-step explanation:
The question 'Which is a complete sentence?' pertains to English grammar and sentence structure. A complete sentence must have at least a subject and a predicate, forming a complete thought. Looking at the options provided:
- Option A: Lewis and Clark and their team began their westward expedition in St. Louis in 1804. is a complete sentence. It has a subject ('Lewis and Clark and their team') and a verb phrase ('began their westward expedition in St. Louis'), which together express a complete thought about the historical journey of the Lewis and Clark Expedition.
- Option B: We had an abundant harvest from our garden this year, we have plenty of squash and tomatoes. is not a complete sentence but a run-on sentence, which could be corrected by splitting it into two sentences or using a conjunction.
Therefore, the correct answer is Option A.