Final answer:
The reaction described is a double-replacement reaction, where two compounds exchange parts, resulting in new substances. Therefore, the correct option is E.
Step-by-step explanation:
The reaction type described in the question, Element A + compound B ————> element C + compound D, is a double-replacement reaction. In a double-replacement reaction, two compounds exchange parts with each other, typically resulting in the formation of a new precipitate, gas, or molecular compound like water. The general formula for this type of reaction is AB + CD —→ AD + CB, where A and C are cations and B and D are anions. This reaction typically occurs in aqueous solution.
A single-replacement reaction involves one element replacing another in a compound and follows the general form A + BC —→ AC + B for metals, and Y + XZ —→ XY + Z for nonmetals. However, the reaction in the question does not match this form, since it involves two compounds rather than an element and a compound reacting.
Thus, the correct answer to the student's question is E. Double Replacement.