Before Surgical Removal of a Diseased Parathyroid Gland, Two Tests

Before surgical removal of a diseased parathyroid gland, two tests are often performed: the standard intact test and the turbo test. Both tests measure parathyroid hormone (PTH, in ng/l) , but the turbo test is very expensive. Researchers obtained data from both tests in a sample of 48 patients to predict turbo test results (y) from standard intact test results (x) . The data ranged from roughly 0 to 500 ng/l, and a scatterplot showed a clear linear relationship. The published findings are summarized exactly as follows:
Y = 1.08x - 4.36 (r = 0.97; n = 48)
What is the slope of the regression line?

A) -4.36
B) 0.97
C) 1.08
D) 48