Final answer:
The alkaline earth metal found in Period 4 is calcium (Ca).
Step-by-step explanation:
The alkaline earth metals, which include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra), are found in Group 2 of the periodic table. These elements are typically shiny, silvery-white, and somewhat reactive, with varying abundance and reactivity. In Period 4 of the periodic table, the alkaline earth metal that can be found is calcium (Ca), which makes the answer to the student's question (C) Ca.