4. Select a time equation for scquiring books and one for acquiring joumals. a. T=S (number of selections) +15 (number of requests) +11 (number of orders) +6 (niumber of invoices) +12 (number of units received) b. T=6 (number of selections) +5 (number of requests) +15 (number of orders) +12 (number of invoices) +11( (number of units received) c. T=11 (number of selections) +6 (nimber of requests) +12 (nimber of arders) +15( number of invoices) +5 (number of units received) d. T=12 (number of selections) +11 (number of requests) +15 (number of orders) +12 (number of invoices) +5 (number of units received) e. T=15 (number of selections) +12 (number of requests) +5 (number of orders) +12 (number of invoices) +6( iumber of units received) Select: Using the time equations, caiculate the unit costs for acquiring books and journals. Round your answers to the nearest cent. 5. Suppose that some professors respond with a request for a book or fournal that is not on the fist provided by the ibvary. In such cases, it takes an additional two minutes read and repiy. Select, how would you modity the time equations in Aequirement 4 to deal with this additional complexty? a. T=6 (number of selections) +(S+20 (if request is not on the list ) (number of requests +15( number of ordern )+12( niember of invoices )+11( namber of units received). selections) received) received) selections)