A fund manager has a bond portfolio worth $10 million. The duration of the portfolio in four months will 6.2 years. She decides to reduce the duration to 4.2 years over the next four months, by using six-month Treasury bond futures contracts. The Treasury bond futures price is currently 117'15. The cheapest-to-deliver bond has duration of 7.3 years. The fund manager should: A) enter a long position in 23 Treasury bond futures contracts B) enter a long position in 72 Treasury bond futures contracts C) enter a short position in 49 Treasury bond futures contracts D) enter a short position in 72 Treasury bond futures contracts E) enter a short position in 23 Treasury bond futures contracts