[单选题]
An electron is moving abq+ cgq;d sk)i-out ak xt8l-h*0n vx :yydu +gwws,z2 wzc:+c9oms - single proton in an orbit characterized by n = 4. How many of the electron's de Broglie wavelengths fit 9ysv,w:2 + coxwzl-x+t-c*kmuyzn8g:swdh0 into the circumference of this orbit?