Correct option is D
The correct sequence is
RQSP.
·
R (my brother and I): The sentence begins by introducing the subjects who are planning something.
·
Q (are planning to throw): This follows the subjects to state their intention or action.
·
S (a surprise party for): This phrase specifies what they are planning, i.e., a surprise party.
·
P (my mother on her 40th birthday): This part clarifies who the party is for and the occasion.
The sentence thus becomes: "
My brother and I are planning to throw a surprise party for my mother on her 40th birthday," which is grammatically correct and meaningful.