Ideal M voltmeter reading in circuit diagram

[vivek_luv4u]

In the given figure an Ideal M voltmeter is shown. M will read:
a)7.07 v b)12.24 v c)14.14 v d)20.0 v.

Its my request to solve step by step ,that I can understand easily, not only mention the answer, please clear it how it comes..



the circuit diagram is in the attachment...

 

[Integral]

Show us what you have done.