In the context of the proof that the product of \( \frac{a}{b} \) and \( \frac{c}{d} \) leads to a valid fraction, the Closure Property tells us about the behavior of integers under multiplication. Specifically, the products \( a \cdot c \) and \( b \cdot d \) are both integers since they result from multiplying integers \( a \) and \( c \), as well as \( b \) and \( d \).
Therefore, the correct answer is:
2 for option 2: They are both integers.