Please help me asap! Could you please explain how you got the answer

Complete the two-way frequency table below, which shows the relationship between students who enroll in advanced Algebra and Physics in a particular high school. From a sample of 30 students, it is found that 19 are taking Algebra, 12 are taking Physics, and 4 are enrolled in both. How many students are enrolled in either Algebra or Physics?


Algebra Not in Algebra Total

Physics 4 --------- ----------------------------12

Not in Physics

Total 19---------------------------------------30


A.) 27

B.) 23

C.) 3

D.) 4