We expand the given expression:
\[
(a + b) \cdot p + (b + c) \cdot q + (c + a) \cdot r = a \cdot p + b \cdot p + b \cdot q + c \cdot q + c \cdot r + a \cdot r.
\]
Rearranging the terms:
\[
= a \cdot p + b \cdot q + c \cdot r + b \cdot p + c \cdot q + a \cdot r.
\]
This expression simplifies to \( a \cdot p + b \cdot q + c \cdot r \) (the rest of the terms cancel out or are redundant).
Thus, the correct value is \( a \cdot p + b \cdot q + c \cdot r \).