Kebri LTD. sells Radios and Televisions. They have recorded their monthly revenue as follows: 
Revenue in Ksh '000' (Y): 321, 287, 209, 397, 388, 224, 344, 464, 433, 315 
Radio Units (X₁): 58, 71, 95, 105, 114, 126, 171 
What is the coefficient of determination (R²) for the relationship between revenue and radio units? 
a) 0.724 
b) 0.835 
c) 0.903 
d) 0.654