What is the weighted average beta of the following portfolio?

-Stock L has a beta of 1.45 and constitutes 10% of the portfolio

-Stock M has a value of $125,000 with a beta of 0.93

-While Stock N makes up 40% of the portfolio with a beta of 0.65 and

- Stock O, with a 2.2 beta has a dollar value of $175,000

a.) 1.24

b.) 1.31

c.) 1.54

d.) 1.76

Please explain