Consider the basic COCOMO model where $E$ is the effort applied in person-months, $D$ is the development time in chronological months, $KLOC$ is the estimated number of delivered lines of code (in thousands) and $a_b, b_b, c_b, d_b$ have their usual meanings. The basic COCOMO equations are of the form

In the standard Basic COCOMO (Constructive Cost Model):

1. Effort ($E$):

   $$E = a_b (\text{KLOC})^{b_b} \quad \text{in person-months}$$

   Here, $\exp(b_b)$ represents the exponent $b_b$.

2. Development Time ($D$):

   $$D = c_b (E)^{d_b} \quad \text{in months}$$

   Here, $\exp(d_b)$ represents the exponent $d_b$.

Comparing these standard formulae with the options:

• (A) correctly defines $E = a_b (\text{KLOC}) \exp(b_b)$ and $D = c_b (E) \exp(d_b)$.

• Options (B), (C), and (D) mix up the variables (such as calculating $D$ directly from $\text{KLOC}$ or swapping parameters).

Hence, the correct option is A.