The static head of the system is B+D-A. But A may possibly be lowered to the minimum level, and can be removed from the equation for a conservative approach.
The maximum total static head is the lowest level in the supply tank to the highest discharge point on the discharge side. Total head for the pump to generate is another calculation.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
"Total static head" though doesn't really mean much unless you make some assumptions / state the process and where you are trying to measure the said static head.
From your statements and drawings it looks like
a) the assumption is that the pipe is fully filled with liquid (water?)
b) the top of the pipe is open to atmosphere
c) There is an NRV in the pump discharge
d) Your question is really about what is the differential head across the pump which is required to make it flow (Total Static head plus frictional losses)
Then yes the answer is (B+D) -A
If thought the question was what is the total static head at lowest point then it would be B+C+D.
Any other location would be a different answer.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
