What does it mean gradually?

From the following responses, select the statement that is grammatically incorrect. a. i forgot my umbrella today and became sopping wet on my way to work. b. because i forgot my umbrella today, i became sopping wet on my way to work. c. today i forgot my umbrella, on my way to work i became sopping wet. d. having forgotten my umbrella today, i became sopping wet on my way to work. e. i forgot my umbrella today; hence, on my way to work i became sopping wet.