The correct answer is A. 69.72%.
The budgeted indirect cost rate is calculated by dividing the budgeted cost in the indirect cost pool by the total quantity of the cost allocation base. In this case, the budgeted cost in the indirect cost pool is $139,600 and the total quantity of the cost allocation base is $155,600. Therefore, the budgeted indirect cost rate is $139,600 / $155,600 = 0.8972 = 69.72%.
Option B is incorrect because it is the budgeted cost in the indirect cost pool divided by the total quantity of the cost allocation base, multiplied by 100%. This gives the budgeted indirect cost as a percentage of the total cost, not the budgeted indirect cost rate.
Option C is incorrect because it is the total quantity of the cost allocation base divided by the budgeted cost in the indirect cost pool. This gives the cost allocation base as a percentage of the budgeted indirect cost, not the budgeted indirect cost rate.
Option D is incorrect because it is the budgeted cost in the indirect cost pool divided by the total quantity of the cost allocation base, plus 100%. This gives the budgeted indirect cost as a percentage of the total cost, plus 100%, not the budgeted indirect cost rate.