To answer this question, you need to understand the rules of scoring in tennis before 1986.
Before 1986, players could only win a point if they had served the ball. Therefore, the correct answer is option C) served. This option is correct because it accurately reflects the rule that was in place before 1986.
Option A) received - This option is incorrect because before 1986, players could not win a point by receiving the ball.
Option B) aced - This option is incorrect because before 1986, players could not win a point by acing their opponent.
Option D) both B and C - This option is incorrect because the correct answer is option C) served. Option D implies that both acing and serving were ways to win a point, which is not accurate for the time period specified.