Answer:
Option C=> to encourage people to vote for Gerald Ford.
Step-by-step explanation:
The main clue in order to solve this question is the main part of the question that says; '' The billboard shows Gerald Ford before the 1948
Republican primary" that is to say that the Billboard was not showing another person's picture than that of Gerald Ford.
Gerald Ford is the 38th United States of America President and he was born on the 14th day of the month of July, in the year 1913 and he died on the 26th day of the month of December, in the year 2006.
The Billboard picture of Gerald Ford is acting as a political propaganda that is been used by politicians to solicit for votes. Hence, Gerald Ford wants people to vote for him by publicizing himself.