A particle is acted upon by constant forces 4 i + j -3 k and 3 i - j - k which displace it from a point i + 2 j + S k to the point 5 i + 4 i + k. The work done in standard units by the forces is given by
(a) 40 units
(b) 30 units
(c) 25 units
(d) 15 units
