At the grocery store last week, small boxes of facial tissue were priced at $4$ boxes for $\$5.$ This week they are on sale at $5$ boxes for $\$4.$ The percent decrease in the price per box during the sale was closest to: $\bullet$ A. $30\%$ $\bullet$ B. $35\%$ $\bullet$ C. $40\%$ $\bullet$ D. $45\%$ $\bullet$ E. $65\%$ Select the most appropriate letter.