Correct Option: A

The given circuit:

Applying KCL at node C,

=	VC - VA	+	VC - VB	+	VC	= 0
	14		1		2

or

Vc		1	+	1	+	1		=	VA	+	VB	=	100	+	40
		14		1		2			14		1		14		1

or

Vc		1 + 14 + 7		=	100 + 40 × 14
		14			14

or
VC = 30V
Now, current in 14Ω resistor,

I14Ω =	100 - VC	=	100 - 30
	14		14

= 5A
So,
I_R = 10 – 5 = 5A
and

R =	VA - VB	=	100 - 40
	IR		5

or
R = 60/5 ≈ 12Ω
Hence alternative (D) is most correct choice.