If the dividend and the divisor have like signs, then the sign of the quotient is ________.

The correct answer is: Positive

There are only two signs, positive and negative. When the dividend and the divisor have the same sign, then the quotient would always be positive. That is,
When they positive, obviously the quotient becomes positive. When they are negative, there would be negative for the dividend and the divisor which would cancel each other thus making the quotient positive.
Hence, the correct answer is option a.