Algebraic Patterns in Equivalent Fractions

Q.

If $\frac{a}{b}$ = $\frac{c}{d}$, then

which of the following statement is true?

1. $\frac{a}{b}$ = $\frac{a+nc}{b+nd}$

2. $\frac{a}{b}$ < $\frac{a+nc}{b+nd}$

3. $\frac{a}{b}$ > $\frac{a+nc}{b+nd}$

4. $\frac{ac}{bd}$ =1