In a cross of AB and ++, 750 are parental types out of 1000 progenies. The map unit between A and B is

Answer: Option A

In a cross of AB and ++, 750 are parental types out of 1000 progenies. The map unit between A and B is 75 map units.
A map unit is a unit for measuring genetic linkage. It is defined as the distance between chromosome positions for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01.
Map unit between A and B
$$\begin{array}{rl}& =\frac{\text{no}\text{. of recombinants}}{\text{total no}\text{. of offsprings}}\\ & =\frac{750}{1000}\times 100\\ & =75\text{ maps unit}\text{.}\end{array}$$