Right option is (c) Enzyme attached to the inside of the cylindrical fiber
Best explanation: The concentration profile of flat surfaces is perfectly linear. The unusual ones are the curved surfaces such as spherical particles, the inside of cylindrical tubes or the outside of cylindrical fibers which produce non-linear concentration profiles. This is because of the substrate molecules approaching the surface through different pathways like convergent or divergent in nature. Hence the above concertation profile represents the enzyme attached to the inside of the cylindrical fiber. The black line represents r/ƍ = 9 and red dotted line represents r/ƍ = 0.11. Also, µ = 10^-3, 1 and 10^3 for the top, middle and bottom pair of curves, respectively.