What Is the Equivalent Resistance Between Points a and B $\Omega$

Multiple Choice

What is the equivalent resistance between points a and b when R = 13 $\Omega$ ?

A) 29 $\Omega$
B) 23 $\Omega$
C) 26 $\Omega$
D) 20 $\Omega$
E) 4.6 $\Omega$