Pick up the correct statement from the following:

• The topographical maps of the Survey of India are useful in the mountainous region for tunnelling.
• The height point on the ridge is fixed with the help of reciprocal ranging
• The accuracy of 1 in 10, 000 is required for planimetric control
• 1 second theodolite is used for angular measurement to achieve an angular error of 15 N where N is number of angles
• All the above.