Solve the Problem $69 \mathrm {~cm}$ the Triangle Is Isosceles Now, but If Its Base

Multiple Choice

Solve the problem.
-The perimeter of a triangle is $69 \mathrm {~cm}$ . The triangle is isosceles now, but if its base were lengthened by $2 \mathrm {~cm}$ and each leg were shortened by $4 \mathrm {~cm}$ , it would be equilateral. Find the length of the base of the original triangle.

A) $21 \mathrm {~cm}$
B) $25 \mathrm {~cm}$
C) $18 \mathrm {~cm}$
D) $19 \mathrm {~cm}$