Which one of the following sets of monosaccharides forms sucrose?

• A
  $\beta-D$-Glucopyranose and $\alpha-D$-fructofuranose
• B
  $\alpha-D$-Glucopyranose and $\beta-D$-fructopyranose
• C
  $\alpha-D$-Galactopyranose and $\alpha-D$-Glucopyranose
• D
  $\alpha-D$-Glucopyranose and $\beta-D$-fructofuranose