Comparison of Total Product Sales

The table below displays the monthly sales data (in thousands of units) for three products (A, B, and C) over the first four months:

Using this data, answer the following questions:

Let the total sales for each product over the four months be represented as:

$$ S_A = A_{Jan} + A_{Feb} + A_{Mar} + A_{Apr} $$

$$ S_B = B_{Jan} + B_{Feb} + B_{Mar} + B_{Apr} $$

$$ S_C = C_{Jan} + C_{Feb} + C_{Mar} + C_{Apr} $$

Which of the following statements is true?