The table above shows Randy's Shirts' short$-$run production function. Randy hires workers at a wage rate of $$50$ a day and his total fixed cost is $$100.$ a$)$What is the marginal product of the $3$rd worker?b$)$ What is Randy's average fixed cost if $48$ shirts are produced?c$)$ What is Randy's total cost if $48$ sweaters are produced?