The correct option is
D Q S R P
Every sentence starts with a subject. Subjects are nouns that are followed immediately by verbs and the option "Q" has a noun with a verb following it. So, the subject in this sentence has to be "you," which is in the option "Q." Hence, "Q" is the first option.
"Q" also has the verb "should have." Verbs are followed by objects. The only object is in the option "R," which is "blood pressure." But the sentence is about "you." Thus, we're referring to "your" blood pressure. So, the next two options are "S" and "R": "your" "blood pressure."
The sentence uses the structure of "have something done," which is "have + noun + past participle" in grammar terms. The noun is "blood pressure", which option "R" contains. The past participle "checked" is contained in "P." That gives us "have + your blood pressure + checked." Hence, the last entry in the sequence is "P."
The full sentence is "You should have your blood pressure checked regularly." Hence, option C is correct.