What is the formula of dimensionless skin obtained from Drill Stem Test?

• A. S = 1.151[{(Pwf– P1hr)/m}-log(k/(φμcrw2)+3.23]
• B. S = 3.23[{(P1hr – Pwf)/m}-log(k/(φμcrw2)+1.151]
• C. S = 1.151[{(P1hr – Pwf)/m}-log(k/(φμcrw2)]+3.23
• D. S = 1.151[{(P1hr – Pwf)/m}-log(k/(φμcrw2)+3.23]