Answer
$V_C-V_A=2.46V$
Work Step by Step
It is clear from the figure that $B$ and $C$ are the same potential. Therefore,
$V_B=V_C$
Hence, it an be concluded that:
$V_C-V_A=V_B-V_A$
Also, from part (a), we know that:
$V_B-V_A=2.46V$
Thus, it is clear that:
$V_C-V_A=2.46V$