The correct answer is B. Derek carefully loaded his drums into his car, and then he goes and locks the keys inside.
Step-by-step explanation:
In writing, sentences and paragraph should use appropriate verb tenses, this implies using the type of tense that is appropriate to the situation, for example, events of the past can only be expressed using past tense and also by using only one type of tense, which means a sentence or paragraph in most cases only include a type of tense (present, future or past) except if the writer includes events that occur in different times.
In the case of the sentence "Derek carefully loaded his drums into his car, and then he goes and locks the keys inside" this contains an error in verb tense because the author of this sentence seems to be describing the actions Derek performed in the past and this implies only past tense should be used; however the author has used "loaded" which is adequate because it is in simple past but later the author unexpectedly changes to present as in "goes and locks" which is not appropriate and an error in verb tense.