What does this prohibition sign with additional sign mean?

Is it allowed to park and stop on the right side?

• A

  Allowed

• B

  Unauthorized

  According to the National Technical Regulation on Road Signs QCVN 41:2019, the "no stopping and parking" sign (symbol P.130) prohibits motor vehicles from stopping and parking on the side of the road where the sign is placed, except for priority vehicles as prescribed. For buses running on the prescribed route, they are guided to the appropriate stopping position.
  Sub-sign number S.503a is placed below the "no stopping and parking" sign to indicate the direction of the sign's effect is to the right.

Japanese

Source: https://vtcnews.vn/bien-bao-cam-kem-bien-phu-nay-co-y-nghia-gi-ar859343.html