Give a reason for your answer to the following question. Assume that all variables represent integers.
Is $4a$ a factor of $2a \cdot 42b$?
Yes, because $4a$ is a divisor of $42b$.
Yes, because $2a \cdot 42b = 4a \cdot 21b$ where $4a$ and $21b$ are integers because $a$ and $b$ are integers and products of integers are integers.
Yes, because $4$ is a multiple of $42$.
No, because $42$ is not a divisor of $4$.
No, because $2a \cdot 42b = 4a \cdot 21b$ where $4a$ and $21b$ are not necessarily integers because products of integers are not always integers.
