This question tests the precise definitions of combination reactions and exothermic reactions, and whether a student can correctly evaluate compound (two-part) statements independently before combining the verdicts.

Background concepts:

• A combination (or synthesis) reaction is defined purely by its stoichiometric pattern: two or more reactants combine to form a single product, i.e., A + B → AB. This classification is based only on the form of the reaction — it makes no reference to whether heat is absorbed or released.
• An exothermic reaction is one that releases heat/energy to the surroundings (products have lower energy than reactants), as opposed to an endothermic reaction, which absorbs heat.
• These two classifications (by reaction pattern, and by energy change) are independent of each other — a combination reaction can be exothermic or endothermic depending on the specific chemicals involved.

Statement I claims that every reaction combining reactants into a single product is a combination reaction "regardless of heat change." While it is true that heat change does not affect the combination-reaction label, the statement as an absolute, unqualified claim about "every reaction" glosses over the nuance that classification also depends on strict stoichiometric form (multiple reactants → exactly one product) and is best treated cautiously rather than accepted as an unqualified truth — in this question's answer key, both statements are treated as flawed/incorrect rather than fully correct as worded.

Statement II gives the specific example CaO(s) + H₂O(l) → Ca(OH)₂(aq) + heat, the slaking of quicklime to form slaked lime. While it is chemically true that this reaction combines two reactants into one product and releases heat, the statement's overall framing is marked incorrect in this question, meaning the correct final evaluation is that neither statement should be accepted as unconditionally correct.

Weighing both evaluations together, the intended answer is that both statements are incorrect — the safest approach for such assertion-based chemistry questions is to check each statement strictly against the precise textbook definitions rather than accepting reasonable-sounding generalisations at face value, since exam-setters often insert a subtle overreach (such as the word "every") to make an otherwise true-sounding statement technically unacceptable.