The formulas of A and B are the following reaction sequence.
\( \mathrm{A = C_7H_{14}O_8,\; B = C_6H_{14}} \)
\( \mathrm{A = C_7H_{13}O_7,\; B = C_7H_{14}O} \)
\( \mathrm{A = C_7H_{12}O_8,\; B = C_6H_{14}} \)
\( \mathrm{A = C_7H_{14}O_8,\; B = C_6H_{14}O_6} \)