6. (10 points) Four people, A, B, C, and D, each contributed the same amount of money to order several New Year's gifts of the same specification. After the gifts were purchased, A, B, and C each took 3, 7, and 14 more gifts than D, respectively. During the final settlement, B paid D 14 yuan and did not pay A any money. How much more money should C pay D ( ) yuan?
A. 6
B. 28
C. 56
D. 70
【Solution】Solution: If four people spend the same amount of money, each person can get the gifts: $a+\frac{3+7+14}{4}=a+6$ (pieces) The price of each gift is: $14 \div(7-6)=14$ (yuan)

What Bing should pay to Ding:
$$
\begin{array}{l}
14 \times[14-6-(6-3)] \\
=14 \times[8-3] \\
=14 \times 5 \\
=70 \text { (yuan) }
\end{array}
$$

Answer: Bing should pay Ding 70 yuan.
Therefore, the correct choice is: D.