What is efficiency? A. The ability to do something well without wasted time or effort
B. Doing more than one task at a time
C. The activity of selecting what to do next
D. A measure of output for any given project, task, or activity

the second sentence is a great revision in my opinion. that would be a great topic.

explanation:

it is believed to be alfred, lord himself

sentence lenght varies according to word choice.you select which word to use and that will require to use other expressions that collocate with the word chosen.sentence length will vary   according to the choice of words you make to express your ideas.