An exposure was made at 40-inch SID using 5 mAs and 105 kV,…

An exposure was made at 40-inch SID using 5 mAs and 105 kV, using an 8:1 grid. Another image of the same part is made using a 12:1 grid and 90 kV. Which of the following exposure times will be most appropriate, using 400 mA, to maintain the original receptor exposure.