A two variable sensitivity analysis on the income statement of Company XYZ reveals that a $10\%$ increase in sales revenue combined with a $5\%$ decrease in cost of goods sold leads to a $15\%$ increase in net income. Analyse the synergistic effect of these changes and explain how they contribute to the overall profitability of the company.

A$)$ The changes in sales revenue and cost of goods sold have an independent impact on net income

B$)$ The changes in sales revenue and cost of goods sold have an multiplicative effect on net income

C$)$ The changes in sales revenue and cost of goods sold have an diminishing effect on net income

D$)$ The changes in sales revenue and cost of goods sold have an additive effect on net income